Kenworth HVAC Systems

Mobile Air Conditioning Society Worldwide

2017 Convention

1
 Topics
• Introductions
• System Components
• Kenworth Electrical
• Truck System Information
• B-Cab
• T2000/T700
• NGP 680/880
• Testing/Troubleshooting
• Scan Tool
• K Series Medium Duty
• T Series Medium Duty
• KIMS
2
 Who is PACCAR/Kenworth
PACCAR is the corporate umbrella for truck, and supply related manufacturing
companies, headquartered in Bellevue, Washington. Initially manufactured
railroad cars and logging equipment, starting in 1905.

Heavy-duty truck manufacturing market segments:

• Kenworth Motor Truck Company, USA, in 1945
• Peterbilt Motors Company, USA, in 1958
• Dart Truck Company, USA, in 1958
• Foden Trucks UK in 1981
• DAF Trucks N.V. in 1996
• Leyland Trucks UK in 1998

Truck Subsidiaries:
• Kenworth Mexicana VILPAC 1966
• Kenworth Australia, in 1970
• Paccar Engine Manufacturing NA, in 2010

3
 Kenworth Models
Class 8 – Heavy Duty, Off Highway
+80,000# GVWR
2.3m (Wide Cab)
• T2000 - > T700: No longer produced
1.9m B-Cabs
• T800, W900, T600 -> T660, C500, C550,
T440, 963
2.1m Next Generation Product (NGP)
• Kenworth: T680, T880
• Peterbilt: 579, 567
COE
• K500: Off highway ONLY
• K100: No longer produced
MONSTER TRUCK: up to 400,000# GVWR
• 963/965: Off highway ONLY – modified B-Cab electrics

4
 Kenworth Models
Class 7, 6 & 5 – Medium Duty
33,000# – 16,001# GVWR

• T370, T270, T170 Simplified

B-Cab
Conventional Cab, Electrical
Built in Saint Therese, Canada System
• T370 Class 7: 26,001 - 33,000# GVWR
• T270 Class 6: 19,501 - 26,000# GVWR
• T170 Class 5: 16,001 – 19,500# GVWR

• K370, K270 (LFNA: LF North America)

COE, Cab built in Holland,
Assembled onto chassis in Mexico
• K370 Class 7: 26,001 - 33,000# GVWR
• K270 Class 6: 19,501 - 26,000# GVWR
• Use DAVIE 4 to service cab’s electrical
24VDC– Cab
1 2 V D C – C h a s5 s i s
Kenworth/Peterbilt Model Comparison

6
System Components

7
 Mechanical Components

Most current applications use Sanden, compressors.

SD5H14 and SD7H15

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 Mechanical Components

Condenser, sized per application parameters.

9
 Mechanical Components

Receiver-Drier:
Normal application, absorbs
system moisture and also filters
and stores the liquid coolant
Uses either XH7 or XH9 desiccant
package.

10
Mechanical Components
Expansion Valve

11
 Mechanical Components

Evaporator:
• Changes low pressure liquid into a low pressure
gas by absorbing heat from cab air
12
Mechanical Components

13
Mechanical Components

14
 Electrical

Electrical Systems

15
 Electrical
CAN Electrical Systems Definitions
Definitions
Instrumentation Control Unit (ICU) – 1st generation Instrumentation-only Multiplex
Cab Electronic Control Unit (CECU) – 2nd generation Multiplex, includes systems other than
instrumentation. CECU’s variants relate to vehicle model and the engine emissions standard.
Identifying which CECU in the vehicle helps determine what features are present and also aids
in troubleshooting.

North American MultipleXing (NAMUX) - The CAN electrical architecture used by Kenworth
and Peterbilt Divisions.
Electronic Service Analyst (ESA) - Software Program
needed for all CAN system malfunction code reading and service related
operations. NEXIQ scan tool used with ESA software.

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 Electrical
Kenworth Electrical Systems – 2 Iterations
• Traditional Electrical Systems:
• (Legacy - thru - 2004) – KM815001
• CAN Based Instrumentation:
• ICU – NAMUX (2005-2007) – KM815054/PM819010
• CECU – NAMUX2 (2007-2010) – KM815054/PM819010
• Service manual change, see page 38/39
• CECU3 – NAMUX3/ NAMUX4 (2010 – Present) w/Chassis Node
B-Cab = NAMUX 3 – KM815056 (includes DTC codes)
NGP = NAMUX 4 - KM815057 (includes DTC codes)

17
 Electrical - Typical ICU/CECU Locations

Note: T2000 and T700 is at the front

of the passenger footwell.
2010 emissions compliantT170, T270,
T370 medium duty, is behind the lower
center of the dash panel. Peterbilt
versions, behind the top center of the
dash panel.
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 Electrical - 1st Iteration
Standard Electrical Systems – 1st Iteration
Original Circuit Wiring Key for production prior to phase out for CAN
thru 2004

Brief Examples of Each Category Definition

320 247

10

Models Covered by Elect Wiring Key—T2000, T6/T8/T4, W900B,C500B, K100E

Service Manual KM815001 19

Electrical - 1st Iteration

20
 Electrical - 1st Iteration

Example: this
wire has a code
of C17SR, ORN

21
 Electrical - 1st Iteration

Electrical
Circuit
Matrix
See “Electrical
Circuit Matrix” on
previous page for
instructions on
how to identify
circuit number
and name.

22
 Kenworth Wire Numbering System

P12HN – Kenworth Circuit Code

Circuit function - P
Circuit number
Color of the wire
Destination of circuit or purpose of the circuit
Using Electrical Circuit Matrix

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 Kenworth Wire Numbering System
Example: P12HN
Circuit function - P

P - identifies circuit
function: Power

24
 Kenworth Wire Numbering System

Example: P12HN
Circuit function

Circuit number - 12
Color of the wire

Destination of the circuit or purpose of the circuit

Using Electrical Circuit Matrix

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 Kenworth Wire Numbering System

Example: P12HN 12 - Identifies circuit color:

Green/White

Circuit number -

Color of the wire

12 - Identifies circuit
description:

Horn Relay Hot

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 Kenworth Wire Numbering System

Example: P12HN
Circuit function

Circuit number

Color of the wire

Destination of the circuit or purpose of the circuit -
HN
Using Electrical Circuit Matrix
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 Kenworth Wire Numbering System

Example: P12HN HN - identifies circuit destination

or purpose:

Horn

Circuit purpose – HN

28
 Kenworth Wire Numbering System
Example: GREEN / WHITE

Circuit function

Circuit number

Color of the wire

Destination of the circuit or purpose of the circuit

Using Electrical Circuit Matrix

12

29
 Electrical – CAN Code Designations

• Multiplex migration began in 2004 in models T600, T660, T800, W900,

C500 and Off-Highway models with instrumentation.
• Crossover trucks use a mixture of original circuit designations for existing
electrical truck and chassis components, while “phasing” in the PACCAR
circuit numbering system to support the multiplexed instrumentation
• Circuits numbers and alpha characters used to identify each circuit are much
different than in our legacy circuit wiring key

Service Manual KM815052

30
 Electrical – Can Systems
2005-2010 Multiplex, with ICU, CECU, CECU2, and CECU3 w/o Chassis Node
Circuit Code Numbering and Abbreviations
Example: YEL 2111
YEL— Function: The first three alpha characters represent the color of the
wire and define the primary electrical function of the circuit.
2111— Component: The four-digit circuit code describes the component or
component subsystem that the wire supports. The components and
subsystems are grouped hierarchically.
For example, in the lighting category:

• A general, lighting only circuit is labeled XXX2000.

• A less general, headlamps only circuit is labeled XXX2100.
• A more specific, low beam headlamps only circuit is labeled XXX2110.
• A very specific, left low beam headlamp circuit is labeled XXX2111.

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Electrical – 2nd and Later Iterations
Circuit Code Numbering and Abbreviations
Example: YEL 2111

Additional Wiring Detail Tables

Table 3: Data-Bus Wire Color
Table 4: Trailer/Body Builder Circuits
Table 5: Circuit Code Master List
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 CAN Communication
How many individual CANs may be found on a Kenworth?
• B-Cab? Seven
• T680/880? Eight
• New in 2016 GREEN 9 Pin
• Onboard Diagnostic (O-CAN) to allow direct communication
from DAVIE (scan tool) to the PCI

Aftertreatment (A-CAN) Engine (E-CAN)

Body Builder (B-CAN) optional Frame (F-CAN)

Cab (C-CAN) [T680/880] Instrumentation (I-CAN)
Diagnostic (D-CAN) Vehicle (V-CAN)
 CAN Wire Numbering System
Table 1 Color Codes
Example:

YEL5971

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 35

PACCAR Wire Numbering System

Example: YEL5971 Using the color you can identify
the circuit’s FUNCTION

Red, Yellow, Gray and White are

illustrated below

12V
87A HORN

30
C
87

86 Coil 85

GND
 36

CAN Wire Numbering System

Data-Bus Wire Color

Table 3 — Data-Bus Wire Color

Most common: Color Color DATA Bus

Low side High side
• J1939, YEL & GRN
Light Green Violet SAE J1587 & J1708

• J1587/1708, VIO & GRN Light Green Orange SAE J1922

• Single-wire, BLU Light Green Yellow SAE J1939

Light Green Red OEM, Private bus

Light Green Gray CAN

- Light blue Single-wire bus

 37

CAN Wire Numbering System

Trailer/Body Builder Table 4 — Trailer/Body Builder
Circuits Circuits
Color Electrical Function
These are only on trailer White Ground
circuits inside the green, Black Clearance, ID,
yellow trailer cable jackets Marker lamps
and special body builder Yellow Left turn lamps
circuits. Red Stop lamps
Light green Right turn lamps
Brown Tail lamps
Light blue ABS power, Auxiliary
Electrical – CAN Iterations
2005-2010 Multiplex, with
ICU, CECU, CECU2, and
CECU3 w/o Chassis Node

Service Manual KM815054/PM819010 38

Electrical – Latest CAN Iteration
2010 Multiplexed
Electrical
System Service
Manual —
CECU3
w/Chassis Node

B-Cab = NAMUX 3

Service Manual KM815056/PM819003 39

Electrical – Latest CAN Iteration
2012 Multiplexed
Electrical System
Service Manual
— (P30-1011)

NGP = NAMUX 4

Service Manual KM815057/PM819023

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 CAN – Hub and Spoke
Central hub receives and relays information between different
devices that are on separate CANs

Chassis VGT
Node PCI

CECU
Inst Diag
Cluster
(Hub) Aftertreatment

Cab
Body
(T680)
 CAN – Architecture
Local CAN architecture (A-CAN)

Before NH3
DPF
SCR Senso
Temps
NOx r

Engine Terminating
ECU Resistor

Aftertreatment
ECU DEF
After Level
SCR
SCR
NOx Temps
 CAN – Backbone
Backbone
• Wiring between terminating resistors
• One backbone for each CAN on the truck
• Not one backbone for the whole truck

Backbone is the wiring between

terminating resistors
 CAN – Node
Node
• Device spliced in parallel to the backbone,
this includes wiring from splice to the
device

Node is any device spliced in

parallel to the network
 CAN – Resistors
Terminating Resistor
• Resistor placed at one end of the backbone
• Can be in the harness or inside of an ECU

Node is any device spliced in

parallel to the network
 J1939 – Details
Local ECUs are connected to a backbone circuit

• Backbone will be a twisted pair of yellow and green

wires between the terminating resistors
• CAN Hi Yellow
• CAN Lo Light Green
• Why twisted?

• Any EMI affects both wires

equally and can be filtered out
 Power Distribution Centers
Class 8 – Heavy Duty
Part of IP Harness
• Wide Cab Access: remove glove box
• T2000
• T700

E-Blocks
(16) MAXI fuses
(55) Mini fuses
(4) Diodes
(3) 70A Relays
(11) ISO Relays
(4) Half ISO Relays
(1) Flasher
(12) Spare Power taps
 Power Distribution Centers
Class 8 – Heavy Duty, Off Highway

• B-Cab - Pre 2001: KM815020

• T800, W900, T600, C500
• KM815020, Service Manual

• Engine side molded connectors:

• Chassis Harness (1) 16-way
• Trailer Harness (1) 8-way
• Headlamp Harness (1) 8-way
• Power Feed Harness (1) 1-way
 Power Distribution Centers
Class 8 – Heavy Duty, Off Highway
Cab Side View
• B-Cab - Pre 2001:
• T800, W900, T600, C500
• KM815020, Service Manual

• Cab side molded connectors:

• IP Harness (11) 8-ways
• Spare BATT power strip

Half of the cover’s vents open to the top, letting in

water/snow.
Check bottom row of fuses & relays.
 Power Distribution Centers
Class 8 – Heavy Duty, Off Highway

• B-Cab - Pre 2001:

• T800, W900, T600, C500
• KM815020, Service Manual
Cab Side View
(26) ATO Fuses or
Type 1 Circuit Breakers (before 2001)
Type 2 Circuit Breakers (after 2001)
(14) ISO Relays
(1) Flasher
(1) HVAC Shorting Relay (after 2000)

Relays and circuit breakers in

Driver’s side kick panel
 Power Distribution Centers
Class 8 – Heavy Duty, Off Highway

• B-Cab - Post 2001:

– T8, W9, T6, C5, T440
– KM815055, Service Manual

Engine side connections:

• Chassis Harness, bottom rear
– (1) Deutsch HDP30 29-way
• Trailer Harness, bottom forward
– (1) Deutsch HDP30 9-way
• Power Feed Harness, on box
– (1) Battery cable terminal
 Power Distribution Centers
Class 8 – Heavy Duty, Off Highway

• B-Cab - Post 2001:

– T8, W9, T6, C5, T440
– KM815055, Service Manual

• Part of IP Harness
– Behind clutch pedal
At first covered with metal panel
Later, plastic trim snapped on cover

• Fuse Label
– See ECAT:
S53- XXXX or P53-XXXX
 Power Distribution Centers
Class 8 – Heavy Duty, Off Highway

• B-Cab - Post 2001: KM815055

• T8, W9, T6, C5, T440
• KM815055, Service Manual

E-Blocks
Go to P92-4319 IP Harness drawing
(60) ATO fuses and Type II Circuit breakers
Find CEP (central electrical panel)
(2) 70A Relays:
connector part coils controlled
number: by key switch
______________
(13) ISO Relays
Look
(5) upISO
Half in ServiceNet.
Relays
Depressions let water out
 Power Distribution Centers
Class 8 – Heavy Duty, Off Highway

• B-Cab – 2010 and on:

– T8, W9, T6, C5, T440

• Chassis Load Center

Content varies
Engine Type
Emission Level
 Power Distribution Centers
Class 8 – Heavy Duty, Off Highway
• NGP: T680, T880, 579, 567

Class 7, 6, 5 – Medium Duty

• T370, T270, T170

TIB 34-051 – Probing guide for these load centers

DO NOT USE a test lamp or VOM probes in forked terminals!
• Use MINI fuse cut in half or a blown fuse!
• Use Power Probe #AA4, www.powerprobe.com

GOOD
NO Repair Kit
BAD
 Sun Load Sensor - DTC919

Sun load
Sensor

Sensor resistance across pins A and B is 150K to 190K with no direct

sun light
Sensor should have 5 volts to sensor and 0 to 5 volt signal from
sensor
Check continuity of wires between sensor and HVAC control head
connector

56
 Sun Load Sensor

Secure sensor wiring harness connector to prevent it

from falling down into the dash!
57
Compressor Clutch Relay Circuit - DTC 876

• Check clutch resistance between A and B – 2.8 to 4.4 ohms in clutch

• Check mating connector (A = Gnd and B = 12 V input – need at least
11.5 volts for clutch to operate properly.
• Check control circuit to relay in PDC

58
Outside Air Temperature (OAT) Sensor

• Negative Temperature
Coefficient (NTC) Sensor
• Located on driver’s side
mirror
• Check dash display to
confirm sensor functioning
relative to ambient
temperature

59
 Cab Actuators

• DTC 3981 - panel mode actuator • DTC 520196 - defrost mode actuator

• DTC 3986 - temperature actuator • DTC 520197 - floor mode actuator

• DTC 3984 - fresh / recirc actuator

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 Access to Service Information
Unfortunately due to purely commercial nature of HD and off road, plus
high RD and now governmental regulation costs, access to service
information is strictly controlled.

Kenworth’s primary responsibility is to provide it’s Dealers with up to the

moment information to fulfill warranty responsibilities.

Secondary service information access is available, in various levels and

costs to:
• Fleets
• Direct
• Dealer Sponsored
• Independent Service Providers
• Colleges and Technical Schools
• Body Builders

61
 Access to Service Information
• Paccar, as with all HD manufacturer’s, is very protective of it’s intellectual
information. It does, however, realize that a legitimate need for service
information exists outside the Dealer environment.
• The single “best” approach for ISPs to service information is to develop a
working relationship with your local KW/PB dealer.
• Dealer Sponsored Fleet
• Service Information not for sale otherwise
• ESA/Davie Software/Scan Tool
• Parts
• Fleet Web ECAT (subscription cost type arrangement)
• Service Information, bulletins, specs, and Wiring Diagrams
• Colleges & Technical Schools
• Get a Dealer Sponsored Fleet Designation
• Full access to information, diagrams, flat rate times, etc
• Right to Repair Policy
• Yet to be completed
• Will change policies outlined above
62
Truck System Information

63
 “B” Cab (1.9m cab)
W900 / T440 / T660 / T800 / C500 / 963

64
 Kenworth Models
Class 8 – Heavy Duty:
• B-Cab Series: T440, C500, T600 -> T660, T800, W900

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 Kenworth Models

• Monster Trucks: Off highway heavy duty up to 400,000# GVW

66
 B-Cab: Apr 1994 to Feb 2001

• Pneumatic (air) actuated mode controls

• Cable actuated heater control valve

• 3 Blower fan speeds (Low, Med, High)

controlled by a resistor block

• 1 HVAC Relay (coil grounded through fan switch)

• Binary Pressure Switch

67
 Early Climate Control Compressor
Standard Piston Type Compressor

• Pistons lubricated with oil from

bottom of the case

• Oil level should be measured each

time the system is opened

• Vertical Mount, curved dip stick

• Horizontal mount, straight dip stick

•Discontinued standard use in 2001,

* limited use for some export, non-
emission apps. going forward

68
 B-Cab Controls

Used on B-Cab from 1995 to 2001.

69
 Actuator Control

Early B-CAB uses a

pneumatic
pressure system
for door and vent
controls

Year range:

1995 to 2001

70
 Freeze Switch

Both B-Cab and T2000 use the freeze switch in the ground side
of the HVAC relay control circuit. The freeze switch opens at
31.5° F and closes at 40°F.

(The B-Cab freeze switch is located in the blower housing, on

the engine side of the fire wall)
71
Testing Thermostatic Switch (N/C)
If freeze switch fails closed,
compressor runs all the
time and never cycles –
evaporator eventually
freezes up

If freeze switch fails open,

the compressor will never
engage.

If wrong calibration, we will

not meet duct temperature

72
 Pressure Switch
B-Cab uses a binary cutout switch on the power side of
clutch:

• Low pressure setting

opens at 26 psi

• High pressure setting

opens at 400 psi

73
 B-Cab HVAC Changes By Years
• April 1994 to Feb. 2001: use W/D’s R115-5646, sleeper P94-1333
• March 2001 to Dec 2001 (two HVAC relays and electronic
controls & actuators): use W/D P94-1084
• Dec 2001 to June 2004 (two HVAC relays and electronic
controls & actuators): use W/D P94-1391
• July 2004 to Jan 2007 (added in the linear power module and
electronic actuated water valve (NBI): DO NOT use P94-1459,
use P94-1587. Sleeper use P94-1478
• NAMUX 2 with 07 emissions engine (eliminated binary switch
and added in high and low pressure switches at expansion
valve): use P94-1698
• Changed to NAMUX 3 for 2010 engines and sleeper: use P94-
1852 / P94-1958

74
 Operating Temperatures

If the humidity is over 70%, the duct temperatures will be from normal to 15° higher

75
 B-Cab: Mar 2001 to Dec 2001

• Electrically actuated mode controls

• Cable actuated heater control valve

• 3 Blower fan speeds (Low, Med, High)

controlled by a resistor block

• 2 HVAC Relays

• Binary Pressure Switch

76
Blower Controls

77
 Mode Actuator Specifications

Face Mode, Position 1

11 – 12 volts – signal wire to ground

Bi-Level Mode, Position 2

9 to 10 volts – signal wire to ground

Floor Mode, Position 3

6 – 7 volts – signal to ground

Blend Mode, Position 4

2.5 – 3.5 volts signal to ground
Defrost Mode, Position 5
0 to 1 volts – signal to ground

Fresh Air Position (+) 11-12 volts (A to B)

Recirc. Position (-) 11-12 volts (A to B)

78
 B-Cab: Dec 2001 to June 2004

• Electrically actuated mode controls

• Cable actuated heater control valve

• 3 Blower fan speeds (Low, Med, High)

controlled by a resistor block

• 2 HVAC Relays

• Binary Pressure Switch

79
 Hot Water Valve

Kenworth utilizes hot water valves in many HVAC systems, with two basic types:
Cable operated and Electronic

Cable Operated – T-Series M/D prior to Jan 2016, K-Series M/D, B-Cab prior to July 2004

Electronic – B-Cab after July 2004, T-Series M/D after Jan 2016

80
 Common Issue - Water Valves Leaking
• Complaint
– Water valve rubber seal becomes wedged in valve
which doesn’t allow the driver to shut off the heat

• Cause
– Coolant or Coolant Additives causes rubber to swell
– Chassis Affected
– Legacy models

• Correction
– Revised part implemented
– Gen 2 valve does not have a belt to swell, the housing has a
material developed specifically for Organic Acid
Technology (OAT) coolant which eliminated
stripping/cracking
– Gives enhanced performance using with all typical
automotive coolants, at elevated temperatures and
pressures commonly seen in emissions engines

81
 Early Heater Control Valve - Belt Style
34 Components
Screws (15)
Bushing

Harness O-rings (4)

Actuator Brass roller
pin (4)
Cover
Yoke Belts (2)
Brass
Housing roller pin

82
Heater Control Valve Components – Gen II
11 Components
Screws

Actuator
Cover

Harness O-ring(s)

Valve Stem

Housing
Part # 1000278269BSM

83
 HVAC Control Panel
HOT WATER VALVE
NEW MIXED-MODE CONTROL, CABLE DRIVEN
DEFROST / FLOOR WITH RACK AND PINION
ELECTRIC ACTUATED
MODE CONTROL

ROTARY BACKLIT RINGS FOR

KNOBS WITH NIGHT VISIBILITY
BACK
LIGHTING

AMBER
INDICATOR
LIGHTS

ELECTRIC ACTUATED
TABS ON BOTTOM SNAP RECIR/FRESH AIR SWITCH
INTO DASH
A/C ON/OFF SWITCH
84
 Kenworth HVAC Systems
• B-Cab HVAC Upgrade Changes
• March 5, 2001 through December 2001

85
 P. D. Box Changes
The functions of two relay positions have changed:

1. The ENG RTD 1 relay position has been relabeled as “Cig.

Pwr. Outlet” This jumper wire (P/N VF4111Z01) now
powers the cigar lighter and power wells in the cup
holder. NOTE: The control circuit (85 & 86) is a live circuit
and so if the jumper is replaced with a standard relay, the
circuit will work but there will be a milliamp parasitic draw
all the time

2. The LOW MIR HT. Relay is relabeled “HVAC Control”

and powers the HVAC Control Head and electronic
actuators. The Cab A/C relay still controls HVAC clutch as it
previously did.
86
 P.D. Box
B Cab Upgrade to PD Box
from March 3, 2001 Until
CEP Style was introduced
December 2001

87
 HVAC Relay
B-CAB - Sends Power To The A/C Clutch

88
 B-Cab: July 2004 to Jan 2007

• Electrically actuated mode controls

• Electrically actuated heater control valve

• 2 HVAC Relays

• Linear Power Module

• Binary Pressure Switch

89
Electronic Hot Water Valve

Five Wire Electronic Actuator

90
 Linear Power Module
• Check for a varying voltage on
the gray control wire when
the fan speed knob is moved
on the control head.

• Voltage on the black wire

should also vary in
conjunction with the fan
speed knob and gray control
wire.

• During fan operation, there

may be voltage on the cooling
rods, depending upon fan
speed setting.

Replaces the Resistor Block / Thermal Fuse

91
B-Cab: NAMUX 2 with ‘07 Emissions Engine

• Electrically actuated mode controls

• Electrically actuated heater control valve

• 2 HVAC Relays

• Linear Power Module

• High & Low Pressure Switches

92
 B-Cab low pressure switch
(2007 – present)
Faster cycle times in cooler
• Cut out = 10 +/- 4 PSI weather because low
pressure switches off
• Cut in = 30 +/- 4 PSI
compressor before freeze
switch reaches set point

Low High
Pressure Pressure
switch switch

Fitting Assembly Torque:

3-5 Nm (27-44 in. lbs.)
93
B-Cab Fresh Air Filter

94
 Engine Fan Override Switch

FAN SWITCH

• The fan switch engages the electric engine fan when high side
pressures exceeds 275±10 psi.

• The fan switch disengages the electric engine fan when the high side
pressures fall below 230±10 psi.

• Fan switches on COE models, off highway models and with roof-mounted condensers
may use a fan switch with higher set points. This reduces fan operation because of a
slightly more efficient condenser which causes slightly lower operating pressures.

95
 Engine Fan Override Switch
P92-1873 page 5
P92-2040 page 7
P92-2147 Page 7

Fan Logic for Cat and Cummins are

opposite (Cat - Closed and Cummins -
Open)

Connect wire to 3 J for Cat engines

Connect wire to 3 K for Cummins engines

Note : Connector is found behind the

safety gauge panel.

96
HVAC Duct Work

Release Clip on
Curved glass only

Resistor Pack

97
 Resistor Pack Location
Viewing the Resistor Pack from the firewall

Driver’s side
here

* Must remove cup holder to get at resistor pack. Slide heater

duct towards Driver’s Side
98
Mode Door Actuator

99
 HVAC Unit – Under Hood
Electric Fresh Air/Recirc Actuator
Rated At 221°F

High Density Polyethylene Fresh

Air Duct Rated @ 190°F

100
Electronic Mode Actuator - Behind Glove Box

101
Sleeper Troubleshooting – Temp Sensor Check

Blow gently on sensor and

watch to see that voltage
goes up and returns when you
stop.

Have voltmeter in C77 SU wire and to

ground, to check voltage change when
blowing on Temp sensor

102
Sleeper Troubleshooting Rocker Switch
Rocker Switch Rocker Switch - H124AC = 12 volt supply
(top)

GND = ground (bottom terminal)

C77SU = control voltage (center)

If the switch is in “AUTO” (or open) the

voltage is controlled by the module.

If switch is in “MAX HEAT” C77SU is

switched to Gnd.

If switch is in “MAX A/C” C77SU power

goes through a 1500 ohm resistor.

103
 TIB 01-057 Sleeper HVAC Expansion Valve
If there is no green mark, cut and
peel the black insulating tape from
the end of the expansion valve on
the side facing UP (the end
without the large round disk).

If there is a brass set plug with two

drilled removal tool holes, replace
the expansion valve.

Note: Very Short Production, probably not seen

in aftermarket repair facilities after warranty.

104
 TIB 01-058 A/C Charge Label
• A/C Charge Label on C500, T800 and W900 Day
Cab Chassis, built between 04/14/09 – 09/10/12.

Some customers may realize improved A/C performance with a

refrigerant charge and future recharge to current specifications.
Kenworth has subsequently determined that a more optimal charge is
3lb-7oz to 3lb-8oz, instead of the original 4lb-0oz.
105
B-Cab: NAMUX 3 with 2010 Emissions
(Current Production Configuration)

• Electrically actuated mode controls

• Electrically actuated heater control valve

• 2 HVAC Relays

• Linear Power Module

• High & Low Pressure Switches

106
 R-134a Refrigerant Considerations

• Kenworth uses HNBR O-rings (Hydrogenated Nitrite

Butadiene Rubber) (may be tinted green). Lubricate O-
rings with system specific oil.

• Require special oil - Either POE (Early Climate Control

Compressors) or PAG (Sanden Compressors). Oil used
should not be intermixed.

• DO NOT lubricate slim-line seals on T680/T880 and T-

series MD with oil. These must be installed on clean, dry
fittings.

107
 B-Cab Component Oil Charge

Component Oil Charge

Evaporator 2 ounces
Compressor 2 – 4 ounces (**drain
compressor- balance)
Condenser 1 ounces
Receiver Dryer 0.5 to 1.5 ounces
AC Lines .5 - 1 ounce per line

108
 A/C System Oil Charge Issues
Oil charge imbalance is one of the most frequently
seen problems HD systems.

Signs of potential A/C system oil over-charge include:

• Poor or marginal performance

• Low side line, after evaporator core, sweating
• Excessive oil drained when recovering refrigerant
• History of repeated compressor replacement
• Early compressor failure

109
T2000 / T700

110
Kenworth Models
Wide Cab T2000 - > T700
No longer being produced

111
 HVAC Changes By Years

• 1996 to Oct. 26, 1998 has APADS (A/C Protection and

Diagnostics System): use P94-1125

• APADS Bypass: use P94-1224

• Oct 28,1998 to 2009 factory installed non–APADS: use

P94-1105

• T2000 with NAMUX 2: use P94-1567

• T700: use P94-1944

112
 Heater and A/C Operation

“B” Cab System T2000 System

(T2000 and T700 use a
Bergstrom system)

113
 APADS System
September 1, 1996 through October 26, 1998
First rudimentary full climate control system

Automatic Temperature Control

No A/C switch on the control panel
114
 APADS Bypass
Most APADS Systems Updated (TIB 01-42B)

A/C switch on the right side of the control panel

115
 Non-APADS
October 27, 1998 to NAMUX 2

A/C switch on the left side of the control panel

116
 Control Circuit for the BY-PASS

• T2000 (APADS By-Pass) TIB 01-42A

• When removing APADS, the C102ACP is connected

to the P30CHD changing the High PSI Switch, Low
PSI Switch, and the Freeze Switch to power side
of the control circuit.

117
 Blower Controls

The T2000 has the cab blower circuit wired up as

ground side switching and sleeper blower circuit is the
opposite - power side switching.

118
Fresh Air Door Control

T2000 - uses an
electric actuator to
control fresh air door
using voltages of 12V
and <1V

119
 Mode Control Doors

Put unit into defrost mode before removing unit from under
dash, as the tabs will be damaged during removal otherwise.

120
 Freeze Switch

Both B-Cab and T2000 trucks use a freeze switch in the

ground side of the HVAC relay control circuit

Freeze switch opens at 31.5°F and closes at 40°F

121
 Pressure Switches
T2000 - Uses low and high pressure
switches in the relay control ground circuit.
(Similar to B-Cab after 2007)

• Low pressure settings opens at 10 +/- 4 psi

• High pressure setting opens at 350 +/- 20 psi
122
 T2000 w/NAMUX 2

• Electrically actuated mode controls

• 4 Blower fan speeds (Low, Med-lo, Med,

High) controlled by a resistor block

• 1 HVAC Relay

• High & Low Pressure Switches

• Fan Switch

123
 Operating Temperatures
T2000 R-134a Ambient Sweep Data

Engine Fan on Manual

Engine RPM @ 1500
Doors and Windows Open
124
 Sleeper Control

The Sleeper Rocker Switch controls power to

the Sleeper Control Panel through circuit
number P124SHA.

125
T2000 Sleeper Heater Lines

* No Heat From Cab and/or Sleeper

126
 TIB 01 - 43
1. Run engine to operating temperature

2. Turn Cab & Sleeper heater controls to maximum heat position - (Do not select
Defrost Mode, A/C will cycle and heat up the A/C lines as well).

3. If no heat blows from cab or sleeper heater vents, check for heated coolant flow
through supply lines.

4. If cab and sleeper heater supply lines are at operating temperature and about
the same temperature, then coolant flow may be the problem. Verify correct
operation of HVAC controls and blend air door operation.

Problem

Cure

127
 T2000 Wrap Up
• Why spend time covering an almost 20 yr old
truck system??

• There are still a small number of trucks still

working every day with full OE APADS

• A significant number of trucks still in service

with TIB converted APADS systems

• Most importantly, the TIB converted APADS

systems became the basis for the T700 model
truck A/C system

128
 T700 (All Years)
• Electrically actuated mode controls

• 4 Blower fan speeds (Low, Med-lo, Med, High)

controlled by a resistor block

• 1 HVAC Relay

• High & Low Pressure Switches

• Fan Switch

129
T680/T880
(2.1m Cab)

130
 Kenworth Models
NGP (Next Generation Product)
Kenworth: T680, T880/Peterbilt: 579, 567

131
 Heater and A/C Operation

“B” Cab System T680/T880 uses a

Behr system

132
HVAC Electrical Components
Component B Cab NGP
Compressor Sanden Sanden
AC Relay Yes Controls Yes Controls
power to clutch power to clutch

High Pressure 2007 emissions No

switch engines

Low Pressure 2007 emissions No

switch engines

Binary Switch 1994 - 2006 No

Blower Fan yes yes
switch
Blower motor Yes Yes – but Direct DC Current

Resistor block Cab till 2002 – linear power Still used on all
with thermal then linear module sleeper modules
fuse power module

Freeze switch Yes No

Engine fan Yes No
switch 133
Cab HVAC

134
 Cab HVAC Service Location

• HVAC Components Are Serviced By Removing The Glove Box

And Dash Trim.
• Blower Motor, Actuators, Heater Core, Evaporator, Freeze Sensor, Air
Filter.
• Components Not Serviceable Through Glove Box Opening.
• Plastic Housings, Air Directing Doors, Foam Seals, IP Ducts.

135
 Actuator Service

Actuators In Actuators In
Red Red

• Disconnect battery power from HVAC.

• Remove glove box & b-panels to access actuators.
• Disconnect the wire harness connector.
• Remove (2) T-20 torx screws.
• Replace actuator and connect wire harness.
• Replace trim panels.
• Connect battery power and listen for HVAC to calibrate.
136
 Cab HVAC Unit
Defrost Airflow Fresh/Recirc BLDC Blower
Actuator Airflow Actuator Motor

Panel
Airflow
Actuator
Floor Airflow
Actuator Airflow
Temperature
Actuator
137
Heater Core Evaporator Core
KW Cab Control With Bunk Override

1. Fan Control Dial

2. AUTO Mode

3. Temperature
Control Dial

4. Defrost Button

5. Dash & Floor

6. Dash

138
KW Cab Control With Bunk Override

7. Floor & Defrost

8. Defrost

9. Sleeper Override
(if equipped)

10. Floor

11. Air Conditioner

Enable

12. Fresh Air /

Recirculate

139
 NGP HVAC System
Control

Sleeper HVAC Cab Ductwork

Cab HVAC
Sleeper TXV
Discharge line
Cab TXV

Receiver Drier

Suction Line

Underbody Liquid and

Suction lines

Condenser not
Liquid Line shown

140
 Firewall – Cab Only, HVAC R-134a Lines
Suction Line Clamp Low Side Charge Port

Suction Line

Liquid Line
Receiver Drier /
Liquid Line
Junction
High Side Charge Port 141
 Firewall – Cab & Sleeper, HVAC R-134a Lines
Suction Line Low side Charge Port
Clamp plate

Suction Line

Rubber
Clamps

Receiver Drier /
Liquid line Cab Liquid Line
junction
Sleeper Liquid
High side Line
Charge Port
142
 HVAC - Cab and Sleeper

• Cab
• ATC – Automatic Temperature Control (temperature, mode and fan speed)
• Long-life Brushless DC (BLDC) blower motor – double current component
life
• Lightweight Aluminum Heater Core - serviced thru glove box

• Sleeper
• Register positioning optimizes sleeper airflow
• Filtered & re-circulated air (like home A/C) used to maximize
heating / cooling performance
• Uses an additional recirculation filter in sleeper

143
 Sanden Compressor

• Same Sanden compressor as today

• Slimline seal technology added to NGP
PRV

144
 Discharge Pressure Transducer
Acts as a combination Discharge Pressure Transducer
high/low pressure
clutch switch. It will
disable compressor
when pressure is
above 424 psi or too
low.

Based on an algorithm
using vehicle speed,
pressure reading and
ambient temp over 3
to 5 key cycles.

145
 No fault codes for any HVAC issues

A/C would not cool because compressor would not

engage. ESA showed Pressure transducer pressure at
427 PSI.

Transducer wires at
fire wall connector

146
 Evaporative Thermistor

Settings are approx. 39°F (4°C) and 46°F (8°C)

147
A/C Evaporator Sensor Resistance Values

148
 Cab HVAC Blower Motor

• Brushless DC Motor

• Integrated Linear Power Module is cooled by system air flow

through vented cover.

• Thermally Protected - maximum temperature of 221°F (105°C)

149
 Cab HVAC Blower Motor

• The fan speed is controlled by a 35Hz PWM signal provided by the

control head. Voltage on this wire varies with the position of the
fan knob from ~12V @ low to >1 V @ max.

• This is similar to the LPM control signal on the B-Cab models.

• Do all diagnostic testing in cab with wires connected normally,

DO NOT bench test.
150
 Cab HVAC Blower Motor - DTC 1553

• Check blower operation in manual mode

• Check for good power and ground at blower motor connector

pins 5 (V bat) and pin 1 (Gnd)

• You can not check resistance test through Cab DC motor

• Check wiring continuity between control head and signal wire

151
Testing Brushless Blower

Multi meter have negative lead

in pin 1 and have the positive
lead at PWM input pin 4 to
check for 35hz signal

152
 Slim Line Seals
• Slimline seal technology instead of O-rings

• Superior sealing properties to O-rings

• Slimline technology decrease the leakage rate by more than 50%.

• Slimline seals at ALL A/C connections

Per Parker Engineering (manufacturer of the seals), these are not to be

lubricated during installation.
153
Expansion Valve HVAC Lines - Torque

Component Torque

Expansion valves to 3.3 lb-ft ± 4.5 Nm ± 0.5

evaporator bolts 0.3

All other AC 15.5 lb-ft ± 21 Nm ± 3

connections 2.2

154
 PACCAR Evaporator Line Twist

Bench Top Vice With Evaporator Secured

Hand Held Torque Wrench 155

 PACCAR Evaporator Line Twist
21Nm (per spec) applied to
line fastener nut without
securing TXV will result in
~10-15 degree movement of
TXV due to the liquid and
suction lines relative to
evaporator moving.
Starting Position of TXV Relative to
Evaporator Before Torque Applied

Parts pressure tested using

250psi of Nitrogen and being
held under water for 30
minutes to review for air-
Finished Position of TXV Relative to bubbles (an indication of a leak)
Evaporator after Torque Applied There were no leaks But -
156
 Firewall – Cab & Sleeper, Heater Lines
Heater Core Inlet Heater Core Outlet
Front
View

Bypass Valve
Bypass Return Inlet
Valve
Supply
Outlet Engine Sleeper
Coolant Supply
Tube
Bypass
Valve

Bypass Valve Bypass Valve Engine Cab Heater

Supply Inlet Return Outlet Coolant Supply Tube
157
 Cab Heater By-Pass Valve
• Protects heater core from high coolant pressure/flow
(max is 6.5 GPM).
– Maximizing Life Of Heater Core.
– Allows Flow Up To A Defined Point.
• Valve is flow directional.
• Valve is serviceable as complete assembly.
Into core Out of core

Automatic by-pass
based on Pressure /
Flow curve of spring

Into valve from engine Back to water pump

158
 Sleeper Heater Flow Restrictor

• The flow restrictor reduces the velocity of coolant restricting

coolant flow to less than 5.5 gpm to eliminate cavitation of the
sleeper heater core
• Located under sleeper, in the coolant line.

159
 HVAC System Protection
• Pressure Transducer
• Clutch Disengages at 424 psi (29.3 bar) Locks out compressor at 430 psi (29.6 bar)
• The fan clutch is requested on at 330 psi (22.8 bar) and requested off at 235 psi (16.4
bar)

• Evaporator Thermistor
• Mounted in the HVAC unit
• Clutch Disengages if evaporator temp is 39°F (~4oC) or lower. Clutch is allowed to come
back on when evaporator temperature reaches 46°F (~8oC.)

• Compressor Pressure Relief Valve (PRV)

• Not a serviceable component - part of the compressor

• Relief Valve vents the system at 508-595 psi

160
 Other Sensors
• Cabin Air Temperature Sensor
• Integrated Thermal Optical Sensor, (ITOS sensor)
• Located on the control head

Cabin Temp Sensor

• Sun Load Sensor

• Located on driver’s side of dash panel

• This sensor measures the intensity of the sun and

influences temperature control of the HVAC system

• Do not block this sensor

Sun Load Sensor

161
 Other Components
• Outside Air Temperature Sensor (OAT)

• Located on the bottom of the driver’s mirror

• Resistor

• For the sleeper HVAC unit only

• Is used to control blower speed by varying the

voltage to the blower motor

• Thermal limiter is set at 363°F (184°C)

162
 Sleeper HVAC Overview

• Plastic Housings
• Aluminum Heat Exchangers
• DC Blower Motor With Resistor
• Pleated Air Filter
• 1 Electric Actuator
• Air Temperature Sensor
• TXV
• Service Cover

163
 Sleeper HVAC Components
Heater Actuator Resistor Blower
Core Motor

Air
Outlet

Heater A/C
Connections Filter 164
Tubes
 Sleeper HVAC Control

Fan Control A/C Enable Temperature Control

Note: Sleeper AC function will not work without the sleeper enable
button pushed on the cab HVAC control head.

The Sleeper Control Head “ENABLE” button provides a ground

signal to the Cab Control Head.

165
Performance Testing & Mechanical
Troubleshooting

166
And then the #@$&*
thing just quit working

167
 Repair Strategy
• Verify Complaint
• Visual Inspection
• Record Pressures & Temperatures
Determine if the problem is Mechanical or Electrical!
If it is a Mechanical problem:
• Recover Refrigerant
• Make System Repairs
• Evacuate the System
• Recharge the System
• Performance Testing

168
 Normalized Resting Pressures
RESTING PRESSURE-is the pressure when the AC system has been turned off for
15-20 minutes and equalized. (Chart 7-13)

ARE THE PRESSURES EQUAL ? : Unequal pressures usually means that a

restriction in the system is preventing the high side pressure from flowing into
the low side when the clutch is off.

High pressure - means the system is contaminated (usually with air)

Low pressure - usually means most of the refrigerant has leaked out. Charge
with at least 50 PSI and leak test. (KM811231)

169
Resting Pressures

170
Operating Temperatures

Performance testing:

Fan on high

Doors or windows
open

Switch on fresh air

Manual over ride

switch on (Engine fan
running)

Run engine at 1500 rpm

171
 Leak Testing

1. Make sure A/C system has at least 50 psi refrigerant charge.

2. Make sure detector is rated for type of refrigerant used.

3. Calibrate tester close to where you will be working

4. Hold the tip about 1/2” below where you want to test and move the tip
slowly (moving too fast may push R-134a away).

5. Follow the entire route of the A/C system

6. Test the evaporator by using the blower to clear out residual R-134a, then
wait about 5 min. for more to accumulate and check by inserting test probe
under a dry drip tube.

172
 Leak Testing (Nitrogen)

1. Nitrogen should be used to charge the A/C system, then use soap
solution to look for leaks.

2. Shop air should NEVER be used to check for leaks. Compressed air can
inject moisture into the system, damage system components, and
possibly cause bodily injury.

3. After charging the system with approximately 60-70 (* 200 max) psi of
nitrogen, apply the soap bubble solution to all connections.

4. Bubbles will be generated at any leak site(s).

173
TIB 01-48 Leak Detection Fluorescent Dye

Dye Leak

Dye wafer - Factory

Installed since 10/29/01
174
 Performance Test - Compressor

Fast compressor cycling can be caused by:

• system overcharge
• system contamination
• system undercharge
• bad freeze switch
• checking system at cooler temperatures

Faster cycling times are caused by low pressure side reaching low
pressure switch cut out pressures under low load conditions (low
ambient temperatures) . Sanden recommends no more than 4 clutch
cycles per minute and the suction pressure to be 7 psi or above.

175
 Performance Test - Compressor

It is OK to bypass
low pressure
switch to do
performance test
once you are
sure system is
approximately at
right charge.

176
System Troubleshooting

177
 Evaporator Performance
Check the evaporator performance after the first fifteen (15) minutes of
operation.
• Operate truck with windows rolled down.
• Insert thermometer in center vent while A/C system is operating. Compare reading to
chart to see if within specs.
– A general rule is the difference between ambient and duct temp should be 25 -
30 °f.
• As a secondary check, compare evaporator lines - there should be about a 5 - 15°f
differential. (Temperature differential is very dependent upon ambient conditions,
temperature & humidity).
• Check air flow through evaporator for debris or clogged cabin air filter (usually normal
pressures)
• Check evaporator drains to make sure water is dripping and evacuator valves are on.

178
 Condenser Performance

• Check temperature in (top) and out (bottom) - should be

10 to 15 degree difference. Too much temperature drop
could indicate a restriction. Remember, the temperature
change is not as important as confirming a state change
in the refrigerant.
• Check air flow and obstructions (oil coolers and winter
fronts), bent fins, bent tubes and tight fittings
• Check to see if engine fan comes on, and at the right
pressures
• Check to see that the hood closed correctly.

179
 Saturation Point of Refrigerant
Many refrigerant gauge sets have
an inner scale that reads the
saturation (boiling) point of the
refrigerant.

For the purposes of condenser and

evaporator testing, use an average
value based on the pressures
during compressor cycles. (High
side for condenser, Low side for
evaporator)

Example: Gauge reads between 100 and 300 PSI during compressor cycling. Using an
average of 200 PSI for the high side pressure, from outer scale – refrigerant changes
state at 132 degrees F (inner scale) – use this temp for condenser performance testing.

180
High Side Pressure Chart

High side Temperature at

pressure which change of
state occurs

90 psi 83 degree F
125 psi 100 degree F
150 psi 115 degree F
175 psi 125 degree F
200 psi 130 degree F
225 psi 138 degree F
250 psi 146 degree F

181
Inspecting the A/C System by Temperatures
• When the system is functioning
correctly:
• The pipe between the evaporator
(5) and the compressor (1) should
be cold
• The pipe between the compressor
(1) and the condenser (3) should
be hot
• The pipe between the condenser
(3) and the evaporator (5) (via the
dryer 2) the pipe temperature
should be between hot and cold.

182
Inspecting the A/C System by Temperatures
• Based on the average high
side pressure:
• the temperature of the high
pressure line should be
above the saturation
temperature entering the
condenser
• the temperature of the high
pressure line should be
below the saturation
temperature leaving the
condenser.
? ? • THIS IS CRITICAL for system
performance.

183
A/C System Temperature Inspection
• There should be a ~10 degree
F change across the
evaporator core inlet and
outlet pipes. (This can vary
based on where the
temperature readings are
taken relative to the TXV.)
• The temperature drop from
the center vent should be at
least 20 degrees F.

184
Compressor Clutch Performance

1. Measure available voltage

at the clutch (SYSTEM
VOLTAGE or above 11.5 volts)

2. Measure current draw.

(3.6 to 4.2 amps at 12 volts)

3. Measure Clutch air gap

should be 0.016 - 0.031 inch. 3

185
 Operational Modes – Automatic (ATC)

• The controller will regulate cabin comfort automatically with inputs

from:

• ITOS (in-cab temp) sensor

• Sun Load Sensor

• CECU via C-CAN (incl. coolant temp, outside air temp, engine
coolant temp, engine speed, vehicle speed)

• The control will have a full automatic mode, temperature, and fan
operation once the ATC has been activated.

186
 Operational Modes – Automatic (ATC)
• The controller will regulate cabin comfort automatically with inputs
from:

• ITOS (in-cab temp) sensor

• Sun Load Sensor

• CECU data via C-CAN

• coolant temp

• outside air temp

• engine coolant temp

• engine speed

• vehicle speed

• The control will have a full automatic mode, temperature, and fan
operation once the ATC has been activated.
187
 Operational Modes – Semi-Automatic

• When the HVAC control is placed in Automatic Mode, it is possible to manually

override either the fan speed or the mode setting (floor, panel, bilevel, etc...).

• During the semi-automatic mode, the manually-overridden function will

maintain its state whereas all other functions will vary based off of the ATC-
logic in order to attain the operated requested conditions.

• Please note that the manual override of both the fan speed and the mode
setting will result in the control head returning to a full manual
functioning.

• It should also be noted that the override of the A/C function will place the
control head in full manual mode.

• Selecting the recirculation function makes no functional mode change.

188
Operational Modes – 30% Recirculation

• When in “Fresh Air” manual mode, and the ambient temperature is

below 23°F (-5°C), recirculation door will be set to provide 30%
recirculated air to assist with heater performance.

• Normal operation will return when ambient temperature is above

32°F (0°C).

• Manual over ride (100% recirculation ) is permitted.

• No other mode, including ATC, is impacted.

189
 Operational Modes - Manual
• The HVAC module will keep the following constant:

• blower speed,

• mode position (panel, floor, etc..)

• recirculation (fresh air or recirculated air)

• compressor operation.

• The temperature door is able to reset it's position, to meet the operator-
requested temperature

• The temperature door position is fixed, when the temperature knob is set to
max hot or cold. These are the only conditions where the HVAC operates in a
true "manual" fashion.

190
 ESA Monitors

ESA Scan Tool Monitors

191
 ESA Monitors

• HVAC Switch On/Off

• A/C Compressor Outlet Pressure – Pressure the
HVAC control head is seeing from Pressure
transducer
• Fan Percent On – engine fan request
• Requested Fan Speed – the position of the fan
knob
• Temperature Knob Percent Open – the position of
the temperature knob

192
ESA Interface

193
ESA Interface

194
ESA Interface

195
ESA Interface

196
ESA Interface

197
ESA Interface

198
ESA Interface

199
K370/K270 Cab Over Engine
Medium Duty Trucks

200
Kenworth COE Medium Duty Models
COE Medium Duty Class 5, 6, 7 – K Series

201
 HVAC System Layout

The air conditioning system is a closed system filled with

R134a refrigerant. The A/C Includes a 24V Compressor.
202
 24V Compressor

Sanden Compressor uses a 24 volt clutch

203
24 Volt A/C Compressor Clutch Specifications

• Confirm that the clutch is receiving 22.5 V

(minimum) for 24 V system engagement
• 24 Volt coil resistance should measure between
14.5 Ω and 18.2 Ω @ room temperature
• Air gaps exceeding 0.051” (1.3 mm) can prevent
engagement. Specification is 0.016" - 0.031" (0.4 -
0.8mm).

204
HVAC System Oil Capacities

205
 Condenser Location

Note: Due to the low mount design of

the condenser, road debris buildup
inspection is an initial diagnostic step

206
Receiver-Drier Locations

LFNA Class 6

207
Receiver-Drier Locations

LFNA Class 7

208
Receiver-Drier Locations

LFNA Class 7

209
Receiver-Drier Locations
LFNA Class 7

210
 Evaporator Temperature Controls

• Temperature Switch • Temperature Sensor

• Cut-out temperature of
– Cut-out temperature of
compressor ≤36 °F (≤2 °C)
compressor ≤+32 °F (≤+2 °C)
• Cut-in temperature of
compressor ≥+45 °F (≥+7 °C) – Cut-in temperature of
compressor ≥+45 °F (≥+7 °C)

211
Temperature Sensor Fuse

212
High/Low Pressure Cut-out Switch

• System pressure at which the

compressor is deactivated
<29 psi and >464 psi (<2 bar and >32 bar)

213
 Engine Fan Override Switch

FAN SWITCH

• The fan switch engages the electric engine fan when high side
pressures exceeds 275±10 psi.

• The fan switch disengages the electric engine fan when the high side
pressures fall below 230±10 psi.

• COE, off highway, and models with roof-mounted condensers may use a fan
switch with higher set points. This reduces fan operation because of a slightly
more efficient condenser which causes slightly lower operating pressures.
214
HVAC Control Panel

215
 HVAC Heater Valve

Coolant flow to the

heater core is
controlled by a cable
operated heater valve.

216
 A/C System Operation - Electrical Circuit

The Compressor is energized by VIC via Temperature Switch and Pressure Switch .
The VIC communicates with the engine ECU via V-CAN, and will de-energize the
A/C circuit (GRA5189-0) when coolant temp goes above 216°F (102°C) and re-
energize it when coolant drops below 208°F (98°C).
217
 T170/T270/T370
Medium Duty Trucks

218
Kenworth Medium Duty Models
Medium Duty Class 5, 6, 7 – T Series

219
 T-Series M/D HVAC

• NAMUX 2 for 2010 engines: use P94-1912

• NAMUX 2 for 2016/2017 engines: use S92-1117

(until S94-1007 is released)

220
T-Series M/D - NAMUX 2 with 2010 Emissions
(Pre- 1/11/2016)
• Electrically actuated mode controls

• Cable actuated heater control valve

• 3 Blower fan speeds (Low, Med, High)

controlled by a resistor block

• 3 HVAC Relays

• High & Low Pressure Switches

221
 KIMS
(Kenworth Idle Management System)

222
Kenworth Idle Management System

223
 Kenworth Idle Management System

• KIMS SOP – February 3, 2014

• Available on Model T680
• Peterbilt SmartAir launched July, 2013, all models 48”
sleepers and larger
• PACCAR product is identical with the exception of
condenser location, external refrigerant lines, and
user interface
• Weight is listed at 565 lbs – weight exemption 550
lbs

224
 KIMS Features

• Engine-off No-Idle Operation only

• Ignition Interlock
• Compliments standard sleeper HVAC
• Separate battery bank: 4 Deep cycle AGM
• Alternator requirement-300 amp
• 300 Amp Battery Separator
• Battery Management System (BMS)
• Duct gravity doors
• Vehicle insulation upgrade

225
 KIMS Components
• The main unit resides
under the sleeper bunk
and contains the system’s
evaporator, blower,
compressor and the air
filter.

Since it’s integrated, it has a

very small under-bunk
footprint to maintain
storage space for drivers.
226
Gravity Door
• The gravity door is
located in the fore/aft
factory duct in the T680.
• This keeps the KIMs
system air from flowing
back into the OE unit.

227
 KIMS System Overview

• Sealed Electric
Compressor
• Evaporation Coil
• Suction Line Heat
Exchanger
• Blower Motor Assy.
• Electrical Center
• Serviceable Filter

228
Sealed Compressor
Compressor uses PVE oil
only. Never contaminate
with PAG oil

System can be evacuated

and charged up to 3 times (21
oz or 1.31 lbs)

High Pressure switch

normally closed - will open if
pressure gets too high (non
serviceable)

Thermal limit switch –

normally closed and auto
reset to protect compressor
from high temperatures
229
Evaporator Inlet Filter
• This filter protects the
evaporator coil from dust and
debris. It is washable and should
be serviced periodically during
routine maintenance.

• When necessary, Check Filter

indicator will notify you that the
Evaporator filter must be
cleaned or changed.

• To reset Check Filter: at screen 1

press and hold enter button for
3 seconds.
230
Discharge Temperature Sensor

a.k.a. “the Freeze

Switch”:
This sensor monitors
the evaporator
outlet temperature
as it enters the
vehicle duct system.

231
Linear Power Module

This module controls

the amount of voltage
delivered to the
evaporator blower
creating variable blower
speeds. It is located in
the return air in front of
the evaporator coil.

232
Electrical Center

233
KIMS External Condenser

• The condenser is
mounted to the
exterior of the rear
sleeper wall.

234
 KIMS External Condenser

• Brushless motor
construction
• Quiet airflow
characteristics
235
 KIMS Batteries

Battery
Separator
Solenoid

Four auxiliary batteries are mounted on the exterior of the

vehicle, to power the system in addition to the starting
batteries. 236
 KIMS Batteries
Typical Installation

The four auxiliary batteries are installed in the passenger side

step assembly. This may relocate the SCR & DPF assemblies to
the area between the frame rails.
237
Battery Management System
This device monitors the auxiliary
batteries for state of charge,
communicates with the KIM system
and controls the battery separator
solenoid.

LED light on this device indicates

power to the device and does not
provide diagnostics. Power inputs to
this device are fuse protected.

If one of the BMS fuses blows, the

solenoid will disengage. 238
Battery Separator Solenoid
• This device connects the truck
batteries to the Aux batteries. When
the starting batteries are at or above
13.2 volts, the battery management
device will engage the solenoid to
allow the alternator to charge the
auxiliary batteries.

• When the voltage drops to or below

12.5 volts the battery management
system will disengage the solenoid to
prevent the truck starting batteries
from being discharged below the
engine start level. 239
KIMS User Interface

• User Interface features:

– Default home screen
• Temp set point, mode

– Blower speed control

– Battery “state of charge”

level

240
KIMS User Interface
Icons indicate:

• Fan Speed

• Accumulative hours since last reset

• System error

• Temperature (60 – 85 degrees F)

• Auto temperature control

• Heat manual system mode

• Cool manual system mode

• Check filter – clean or inspect

• Battery health – charge status of

auxiliary batteries 241
KIMS User Interface
• The user interface has a
display screen on the top
and 4 buttons on the
bottom.
• The left button turns the
unit on and off.
• The right button is the
enter button and is used to
select the setting to be
changed.
• The up and down arrows
allow the user to change
system settings.

242
 Turning on the system

Turning the system on requires one of these :

• Key switch in the off position
• Key switch in the accessory position
• Note: There is a 5 to 6 second delay when you key
on and back off for system to shut down
completely
The system will not turn on if the switch is in the
IGN (on) position or the engine is running

243
 KIMS Operation Tips

• Before operating the KIMS HVAC unit, the sleeper

interior temperature should first be brought to the
desired temperature with the engine running, and the
bunk curtain open.
• The KIMS HVAC system is designed to maintain an
established comfortable bunk temperature while the
engine is off and the bunk curtain is closed.

244
 KIMS Tech Tips

• Once the truck is shut down, the driver simply uses

the control panel in the sleeper to maintain
temperature control

• As a safeguard, the system features integrated

power management to maximize cooling
performance.

245
 Retrieving Service Faults

• To enter SERVICE MODE: Push both the ON/OFF and

ENTER button simultaneously, at any time.
• Display will show service indicator and a code #1- #2- #3.
Use up and down arrows to scroll through the Fault
Codes.
• DTC 01 - Evaporator sensor open or shorted high
• DTC 02 - Evaporator sensor shorted low
• DTC 03 - High pressure switch open or shorted high
246
 KIMS w/ KW Auto-Start
The systems are largely independent and they don’t communicate directly with each
other. But here is how they work together:

KIMS is powered from the truck Auxiliary (Aux) batteries.

• KIMS will draw the Aux batteries down to 0% state of charge (SOC) (approx
11.3 V) if Auto Start is not present or enabled

Auto Start monitors the truck Auxiliary batteries.

• If enabled, Auto Start will start the truck when Aux batteries reach 20%

• The batteries will continue charging until the Aux batteries reach 80% then
engine will shut down.

• KIMS will continue to run during auto start engine run

• KIMS shuts off if the key is in IGN to prevent KIMS from being left
running while the truck is being driven. This shutoff does not apply to
Auto Start events
247
 Conclusion

This concludes the presentation.

Thank you for your attention!

Questions?

248
Conclusion

249