Vehicle Improvement Products

SmartWheel Multiplexed Steering Wheel

Troubleshooting Guide

For use with:

Switch Modules SM202, SM204, SM205 and SM208
Master Controls SM203 and SM206

31 March 1998
Revised 13 May 1998
 Vehicle Improvement Products SmartWheel Troubleshooting Guide
PRODUCT DESCRIPTION

The SmartWheel Steering Wheel Control System offers control of the horn, headlamp and marker
lamp flash, cruise control, and wiper functions from a switch panel mounted in the core of the
steering column. The system consists of two electronic modules, the SM202, SM204, SM205 or
SM208 Switch Panel and the SM203 or SM206 Master. Communication between the Switch Panel
and the Master is accomplished via two wires which utilize a dual slip ring in the steering column as
a connecting path to allow for unlimited wheel rotation. The two wires carry a multiplexed
communication signal and power for the Switch Panel. As each switch is closed, the Switch Panel
generates a unique signal which is transmitted to the Master. The Master decodes that signal to
determine which switch is closed and operates the corresponding outputs for that function.

HOW IT WORKS

Functions on the Switch Panel are either momentary or latching. The HORN, HEADLAMP FLASH,
MARKER LAMP FLASH, CRUISE SET, CRUISE RESUME, WIPER PULSE, and WIPER WASH
switches operate in the momentary mode and the corresponding outputs on the Master are only
operated while the switch is pressed. The CRUISE ON, WIPER LO/HI, and WIPER DELAY switches
operate in the latching mode and the corresponding outputs on the master remain actuated until the
corresponding CRUISE OFF, or WIPER OFF switch is pressed or the Ignition input on the Master is
turned off. The WIPER LO/HI switch has the additional feature that initially when the switch is
pressed the wipers operate in the low speed mode and additional operations of the switch cause the
wipers to alternate from the high to low speed modes.

An operational description of each function is as follows:

HORN - The horn switch function on the switch panel is actually accomplished using four switches
located near the center hub on the Switch Panel. If any of these switches is actuated the Switch
Panel will send the appropriate signal to the Master to cause the HORN output (J3-6) to be switched
to ground while the switch is pressed. This output is rated at 0.5 Amps max. at 12Vdc.

HEADLAMP FLASH - Operation of this function rely's on external switching for the headlamp
function. If +12V power is applied to the Headlamp On input (J3-10), +12V power will be removed
from the Headlamp Power output (J3-4 & -9) while this switch is pressed. If +12V power is applied to
the Headlamp Off input (J3-5), +12V power will be applied to the Headlamp Power output (J3-4 & -
9) while this switch is pressed. In this manner, if the headlamps are turned on, pressing the switch
will cause them to go off. In like manner, if the headlamps are turned off, pressing the switch will
cause them to go on. This relay output is rated at 25 Amps max. at 12Vdc. The connector is rated
for 9 Amps.

MARKER LAMP FLASH - Operation of this function rely's on external switching for the marker lamp
function. If +12V power is applied to the Marker Lamp On input (J3-3), +12V power will be removed
from the Marker Lamp Power output (J3-2) while this switch is pressed. If +12V power is applied to
the Marker Lamp Off input (J3-1), +12V power will be applied to the Marker Lamp Power output (J3-
2) while this switch is pressed. In this manner, if the marker lamps are turned on, pressing the
switch will cause them to go off. In like manner, if the marker lamps are turned off, pressing the
switch will cause them to go on. This relay output is rated at 25 Amps max. at 12Vdc. The
connector is rated for 9 Amps.

CRUISE FUNCTIONS:

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 Vehicle Improvement Products SmartWheel Troubleshooting Guide

Because of the requirement that the cruise control functions be extremely flexible to accommodate
the various brands of cruise control systems, the Smart Wheel System incorporates three individual
relays with the normally-open and normally-closed contacts available to those systems. It also
incorporates a programmable jumper field (JP1) which allows the common (armature) contact of the
Cruise On/Off relay to be connected to one of three sources. If the jumper on JP1 is placed in
position "A", the common contact on the Cruise On/Off relay will be connected to the Cruise
Common input (J2-5). If the jumper on JP1 is placed in position "B", the common contact on the
Cruise On/Off relay will be connected to the Ignition input (J1-1). If the jumper on JP1 is placed in
position "C", the common contact on the Cruise On/Off relay will be connected to ground. In order to
insure proper operation of the cruise control system the technician should consult with the chassis
manufacturer to determine the proper jumper setting prior to installing or replacing a Master. In
accordance with many of the cruise control system manufacturer's requirements, these relays are
"dry-circuit" rated with gold plated contacts rated at 1 Amp max. at 12Vdc.

CRUISE ON - Operation of this switch latches the Cruise On/Off relay in the "on" state. This causes
the source determined by the jumper position on JP1 to be disconnected from the Cruise On/Off
normally-closed (N.C.) output (J2-7) and connected to the Cruise On/Off normally-open (N.O.) output
(J2-8).

CRUISE OFF - Operation of this switch unlatches the Cruise On/Off relay. This causes the source
determined by the jumper position on JP1 to be connected to the Cruise On/Off normally-closed
(N.C.) output (J2-7) and disconnected from the Cruise On/Off normally-open (N.O.) output (J2-8). In
essence, this function is inverse to the Cruise On function. This mode is also entered any time that
+12Vdc power is removed from the Ignition input (J1-1) on the Master.

CRUISE SET - Operation of this switch operates the Cruise Set relay while the switch is pressed.
This causes the Cruise Common input (J2-5) to be disconnected from the Cruise Set normally-closed
(N.C.) output (J2-2) and be connected to the Cruise Set normally-open (N.O.) output (J2-1).

CRUISE RESUME - Operation of this switch operates the Cruise Resume relay while the switch is
pressed. This causes the Cruise Common input (J2-5) to be disconnected from the Cruise Resume
normally-closed (N.C.) output (J2-4) and be connected to the Cruise Resume normally-open (N.O.)
output (J2-3).

WIPER FUNCTIONS:
The wiper control functions are implemented via special control circuitry which is intended to control
two wiper motors and maintain synchronization between these motors on each wipe cycle. For that
reason the faster wiper will pause at the end of each cycle and wait for the slower wiper to complete
its cycle before resuming. The control circuitry utilizes dynamic braking on the wiper motors to
eliminate motor coasting. The connections to each of these motors is made via five pin connectors
J6 and J7. The output for the wash pump is J4. The +12Vdc power for all wiper functions is
separate from the +12Vdc power for all other functions and is supplied via connector J5. The ground
connection for the wiper motors should be made to the case of each wiper motor - not to the ground
wire coming from the Master (J6-2 & J7-2). The output rating for all wiper functions is 25 Amps max.
at 12Vdc. Note: If only one wiper motor is utilized a jumper needs to be placed between the PARK
inputs (J6-3 & J7-3) and connected to the PARK contact for that motor.

WIPER WASH - Operation of this switch operates the wash pump relay while the switch is pressed,
causing the Wash Pump output (J4) to be connected to +12Vdc Wiper Power (J5). In addition, if
none of the latching wiper functions (Wiper Lo/Hi or Wiper Delay) had been previously selected, the

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Low Speed Wiper outputs (J6-4 & J7-4) will be connected to +12Vdc Wiper Power (J5) while the
switch is pressed and remain connected for a period of approximately 3 wiper cycles after the switch
is released. If any of the latching wiper functions (Wiper Lo/Hi or Wiper Delay) had been previously
selected, the wipers will continue to run in the selected mode after the wash switch is released.

WIPER PULSE - Operation of this switch causes the Low Speed Wiper outputs (J6-4 & J7-4) to be
connected to +12Vdc Wiper Power (J5) while the switch is pressed. If the latching Wiper Delay
function had been previously selected the wipers will continue to run in that mode after the PULSE
switch is released.

WIPER LO/HI - Operation of this switch initially causes the Low Speed Wiper outputs (J6-4 & J7-4)
to be connected to +12Vdc Wiper Power (J5) continuously. If the switch is pressed again the High
Speed Wiper outputs (J6-5 & J7-5) will be connected to +12Vdc Wiper Power (J5) continuously.
Subsequent presses of this switch will cause alternate operation of the wipers in the low or high
speed mode.

WIPER DELAY - There are two versions of this feature available which are determined by the part
number. On part number SM203, operation of this switch initially causes the Low Speed Wiper
outputs (J6-4 & J7-4) to be connected to +12Vdc Wiper Power (J5) for one wipe and this will be
repeated at a fixed rate of approximately four seconds. On part number SM206 an additional two pin
connector, J8, is provided on the Master so that an external 200K Ohm potentiometer can be
connected as a rheostat to vary the delay time. Operation of this switch on this version initially
causes the Low Speed Wiper outputs (J6-4 & J7-4) to be connected to +12Vdc Wiper Power (J5) for
one wipe and this will be repeated at a rate determined by the position of the external potentiometer.

WIPER OFF - Operation of this switch causes all operation of the wipers to be canceled. This mode
is also entered any time that +12Vdc power is removed from the Ignition input (J1-1) on the Master.

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SYSTEM INTERCONNECTIONS:

SWITCH PANEL:
The switch panel is connected to the slip-rings in the steering column via a two wire pigtail
emanating from the switch panel. The yellow wire is the multiplex Signal wire and the brown wire is
the multiplex Ground wire.

MASTER:
The SM203 Master is supplied with seven connectors. The SM206 Master is supplied with an
additional two pin connector for the variable wiper delay control. A table of the connector types is as
follows:

RECOMMENDED MATING CONNECTOR

CONNECTOR PINS MANUFACTURER HOUSING P/N TERMINAL P/N
J1 6 MOLEX 39-01-2065 39-00-0060
J2 8 MOLEX 39-01-2085 39-00-0060
J3 10 MOLEX 39-01-2105 39-00-0060
J4 & J5 1 ANY 1/4" FEM Q/C
J6 & J7 5 AMP 350809-1 350874-3
J8 2 MOLEX 22-01-2027 08-50-0032

The following is a list of connector pins and their function:

(I= Input, O=Output, P=Power)

PIN TYPE FUNCTION

J1-1 I +12V Ignition from ignition switch or relay
J1-2 & 3 P +12V Power for all functions except wiper power
J1-4 P Power (Chassis) ground
J1-5 I/O Multiplex Ground (to Switch Panel)
J1-6 I/O Multiplex Signal (to Switch Panel)
J2-1 O Cruise Set Normally-Open Contact
J2-2 O Cruise Set Normally-Closed Contact
J2-3 O Cruise Resume Normally-Open Contact
J2-4 O Cruise Resume Normally-Closed Contact
J2-5 I Cruise Common
J2-6 X No Connection
J2-7 O Cruise On/Off Normally-Closed Contact
J2-8 O Cruise On/Off Normally-Open Contact
J3-1 I Marker Lamp Off - +12V input when Marker Lamp Switch is off
J3-2 O Switched +12V Power to Marker Lamps
J3-3 I Marker Lamp On - +12V input when Marker Lamp Switch is on
J3-4 & 9 O Switched +12V Power to Headlamps
J3-5 I Headlamp Off - +12V input when Headlamp Switch is off
J3-6 O Horn - Switched to ground to operate horn relay
J3-7 X No Connection
J3-10 I Headlamp On -+12V input when Headlamp Switch is on

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SYSTEM INTERCONNECTIONS (Continued):

J4 O Switched +12V Power to Wash Pump

J5 P +12V Power Supply for all wiper functions
J6-1 & J7-1 O +12V Power to wiper motors
J6-2 & J7-2 P Ground for all wiper functions
J6-3 & J7-3 I Park Contact inputs for wiper motors (tied together if only one motor is used)
J6-4 & J7-4 O Switched +12V Power to low speed wiper motor input
J6-5 & J7-5 O Switched +12V Power to high speed wiper motor input
J8-1 & 2 I Potentiometer input for variable wiper delay (used only on P/N SM-206)

GENERAL TIPS:
General handling precautions: Electronics are sensitive to static electrical discharge. Handle them as
little as possible. They are most safe from damage when they are in the package or when they are
installed and connected in the vehicle.

The most common problem with any electrical device is usually related to interconnections: wires
and connectors. If the system does not function properly the first thing to check is that all connectors
and wires are properly installed and fully seated making good contact. If the system is partially
functional, i.e., the horn, cruise and lights work but the wipers do not then the problem is likely not
with the multiplex system but with the wiring between the master and the wipers or the wiper system
itself. If the system is completely nonfunctional, start by checking the wiring to the master and from
the master to the keypad.

EQUIPMENT REQUIRED:
1. A Digital Volt/Ohm-meter with an audible continuity check.
2. A low current (less than 0.5 Amp) 12 volt test light.

INITIAL IN-VEHICLE TESTS:

Proceed with these in the order in which they are listed prior to attempting any other in-
vehicle tests.
3. Disconnect connectors J2, J3, J4, J6, and J7 from the Master.
4. Make sure that +12Vdc power is present at J1 pins 2 & 3 and connector J5 on the
Master. If not present, check the supply fuses or breakers.
5. Measure the DC voltage at J1 pin 6 (Multiplex SIG) on the Master. It should
measure in the range of 7-9 Volts. If it doesn't, check the continuity between J1 pin
4 and chassis ground. If continuity exists, replace the Master.
6. Remove the Switch Panel from the steering wheel and disconnect it. Measure the
DC voltage between the wires in the column which were connected to the yellow
and brown wires on the Switch Panel. It should also measure in the range of 7-9
Volts. If it doesn't, check the wiring in the column to the slip rings and Master for
continuity. If it does, reconnect the Switch Panel to the column wiring.

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IN-VEHICLE TESTS:
Perform the Initial In-Vehicle Tests before attempting to performing these tests. Select
these by function if problems are observed with a particular function. Make sure that
connectors J2, J3, J4, J6, and J7 are disconnected from the Master.
HORN TEST - Connect the low current test light between a +12Vdc source and J3 pin 6
(Horn output) on the Master. Press one of the HORN switches on the Switch Panel and
the test light should light. If it doesn't, the Horn output on the Master is defective (replace
the Master).

HEADLAMP "ON" TEST - With no switches pressed on the Switch Panel, check for
continuity between J3 pin 4 on the Master and J3 pin 9, and J3 pin 10. If continuity does
not exist, the headlamp "on" circuitry on the Master is defective (replace the Master).

HEADLAMP "OFF" TEST - While the HEADLAMP FLASH switch on the Switch Panel is
pressed, check for continuity between J3 pin 4 on the Master and J3 pin 5. If continuity
does not exist, the headlamp "off" circuitry on the Master is defective (replace the Master).

MARKER LAMP "ON" TEST - With no switches pressed on the Switch Panel, check for
continuity between J3 pin 2 on the Master and J3 pin 3. If continuity does not exist, the
marker lamp "on" circuitry on the Master is defective (replace the Master).

MARKER LAMP "OFF" TEST - While the MARKER LAMP FLASH switch on the Switch
Panel is pressed, check for continuity between J3 pin 2 on the Master and J3 pin 1. If
continuity does not exist, the marker lamp "off" circuitry on the Master is defective (replace
the Master).

For the CRUISE and WIPER tests below the IGNITION Switch on the vehicle should be
turned to the accessory or run position, causing +12Vdc to be present at J1 pin 1 on the
Master. Note the position of the jumper on the configuration header JP1 so that unit can
be returned to that configuration after the tests have been completed. After that position is
noted, place the jumper in position "A" so that Cruise Common is the source.

CRUISE "ON" TEST - Momentarily press the CRUISE "ON" switch on the Switch Panel.
Because this is a latching function, the function should be active after the switch is
released. Check for continuity between J2 pin 5 on the Master and J2 pin 8. If continuity
does not exist, the cruise "on" circuitry on the Master is defective (replace the Master).

CRUISE "OFF" TEST - Momentarily press the CRUISE "OFF" switch on the Switch Panel.
Because this is a latching function, the function should be active after the switch is
released. Check for continuity between J2 pin 5 on the Master and J2 pin 7. If continuity
does not exist, the cruise "off" circuitry on the Master is defective (replace the Master).

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CRUISE "SET" TEST - With the CRUISE "SET" switch on the Switch Panel not pressed
check for continuity between J2 pin 5 on the Master and J2 pin 2. If continuity does not
exist, the cruise "set" circuitry on the Master is defective (replace the Master). While the
CRUISE "SET" switch on the Switch Panel is pressed check for continuity between J2 pin
5 on the Master and J2 pin 1. If continuity does not exist, the cruise "set" circuitry on the
Master is defective (replace the Master).

CRUISE "RESUME" TEST - With the CRUISE "RESUME" switch on the Switch Panel not
pressed check for continuity between J2 pin 5 on the Master and J2 pin 4. If continuity
does not exist, the cruise "resume" circuitry on the Master is defective (replace the
Master). While the CRUISE "RESUME" switch on the Switch Panel is pressed check for
continuity between J2 pin 5 on the Master and J2 pin 3. If continuity does not exist, the
cruise "resume" circuitry on the Master is defective (replace the Master).
WIPER "WASH" TEST - While the WIPER "WASH" switch on the Switch Panel is pressed,
check for the presence of +12Vdc at J4. If +12Vdc is not present at J4, the wash pump
output circuitry on the Master is defective (replace the Master). In addition, check for the
presence of +12Vdc at J6 pin 4 and J7 pin 4. If +12Vdc is not present, the low speed
wiper wash circuitry on the Master is defective (replace the Master).

WIPER "PULSE" TEST - While the WIPER "PULSE" switch on the Switch Panel is
pressed, check for the presence of +12Vdc at J6 pin 4 and J7 pin 4. If +12Vdc is not
present, the low speed wiper pulse circuitry on the Master is defective (replace the
Master).

WIPER "LO/HI" TEST - Momentarily press the WIPER "LO/HI" switch on the Switch Panel.
Because this is a latching function, the function should remain active after the switch is
released. Check for the presence of +12Vdc at J6 pin 4 and J7 pin 4 on the Master. If
+12Vdc is not present, the continuous low speed wiper circuitry on the Master is defective
(replace the Master). Momentarily press the WIPER "LO/HI" switch again and check for
the presence of +12Vdc at J6 pin 5 and J7 pin 5 on the Master. If +12Vdc is not present,
the continuous high speed wiper circuitry on the Master is defective (replace the Master).
Subsequent presses of this switch will cause alternate presence of +12Vdc at the low
speed (J6 pin 4 and J7 pin 4) or high speed (J6 pin 5 and J7 pin 5) outputs on the Master.

WIPER "OFF" TEST - Momentarily press the WIPER "OFF" switch on the Switch Panel.
Because this is a latching function, the function should be active after the switch is
released. Check for no output at J6 pin 4, J6 pin 5, J7 pin 4, and J7 pin 5 on the Master.
If +12Vdc power is present on any of these output pins, the wiper off circuitry on the
Master is defective (replace the Master). In order to check the dynamic braking circuitry
after the WIPER "OFF" switch is pressed, check for continuity between J6 pin 2 and J6 pin
4 and also between J7 pin 2 and J7 pin 4. If continuity does not exist, the dynamic braking
circuitry on the Master is defective (replace the Master).

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WIPER "DELAY" TEST - This test is fairly complex and, for that reason, it is recommended
that the other functional wiper tests be performed on the system prior to performing this
test in order to isolate the problem. If the unit passes all other functional wiper tests, but
still exhibits a problem in the DELAY mode, momentarily press the WIPER "DELAY" switch
on the Switch Panel. Because this is a latching function, the function should remain active
after the switch is released. Check for the presence of +12Vdc at J6 pin 4 and J7 pin 4 on
the Master. If +12Vdc is not present, the low speed wiper delay circuitry on the Master is
defective (replace the Master). In order to reset the delay timer, momentarily connect the
low current test light from a source of +12Vdc (such as J5) simultaneously to both J6 pin 3
and J7 pin 3 (the "park" switch inputs) on the Master. On the SM203, the presence of
+12Vdc should be interrupted for a period of approximately 4 seconds after the park input
is removed. On the SM206, the variable delay potentiometer should be connected to
connector J8 and the presence of +12Vdc should be interrupted for a period determined by
the rotational position of the remote variable delay potentiometer.

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