Air Conditioning (Front)

From Power Source System A47(A), A48(B), A49(C)

(See Page 100) A/C Control Assembly

10A
GAUGE1
DEFC BLK STX CLK DPD SWD IG
27 A 38 A 37 A 36 A 35 A 34 A 22 C
From Power Source System
(See Page 100)

19 2D
R–L

R–L
(* 2)

15A
A/C

L–O
L–R
R–L

L–B

L–Y
(* 1)

(* 1)

(* 1)

(* 1)

(* 1)
L

6 2D 7 2A 25 2D

R–L

R–L
17 4D
5 6 7 18 19 R–L
B9
BLK STX CLK DPD SWD

R–L
5 4C L–B
DEFC GND IG
R–L C34
2 16 8
(* 2) Center Cluster 1 1
Integration Panel
W–B
R–L

R–L

R–L
(*1)

(*1)

(*1)

(*1)

5 1

HTR Relay
4

3 2

1 1 1
W–B

Y–R
L–R

R–L

Y–R

R–L(*1)
L–B

W–B
1
W–B

W–B

W–B

2 IG5
(* 1)
50A HTR

F19
Fusible
L–R

Link Block 7 3N 34 1A 56 1B
B1
140A ALT

Blower Motor
1 Controller

1 3P 43 1A

2 3
W–B
(* 1)

W–R
W–B

W–B

Battery

18 2E 2 3H

W–R
IF EA II

408
2004 LEXUS LX 470 (EWD546U)
 * 1 : w/ LEXUS Navigation System
A47(A), A48(B), A49(C) * 2 : w/o LEXUS Navigation System
A/C Control Assembly

FRBLW FRHR ALED TEO TW A/CS

23 A
W–R 9 A 4 C 11 A 5 C 7 A

G–B
Y–R

P–B

Y–B

L–B
1 4C 29 2D 12 3N 18 3N 16 3N 14 3N

9 4F 15 2A 33 2D 7 3M 17 3M 9 3M 8 3M

L
W–R

G–B
Y–R

Y–R

P–B

Y–B

L–B
R–L R–L 2 D 13 E 33 D 32 D 14 D 31 D
B9
10 5A ACMG ELS2 ACLD THE THWO A/CS
R–L

LCKI
16 1B 39 5D E 6(C), E 9(D), E10(E) 23 C
Engine Control Module
L

L
MG CLT
Relay

26 1B 8 1B

L
B–Y

R–L R–L

Y–R

R–L(*1) R–L(* 1)

W–B W–B

R–L

4 6
B–Y B–Y B–Y
IG1 IO3
B–Y

3 1

A4
A/C Lock Sensor
A/C Magnetic
Clutch

2
BR

W–R
EC

409
2004 LEXUS LX 470 (EWD546U)
Air Conditioning (Front)

A47(A), A48(B), A49(C)

A/C Control Assembly

FACE B/L FOOT F/D DEF GND VER2 VER4 PSW DGS DGS1
16 A 15 A 14 A 13 A 12 A 12 C 17 C 15 C 8 C 15 B 4 B
BR–W

B–W

L–W

Y–R
P–L
GR

Y
W–B

W–B

W–B
1 2 3 4 5
FACE B/L FOOT FOOT/ DEF 5 5A 10 5B 9 5B
DEF

A A A

18 5D 25 5D 26 5D
M
A J14
Junction

L–W

Y–R
Connector

Y
W–B
46 1B 29 1B 18 1B

46 1A 17 1A 18 1A

+ – L–W
1
A27 6 7
Air Vent Mode Control Servo Motor
Pressure SW
W–B
R–L

Dual

Y–R
Y
A5

22 3N

21 3N 11 3N 27 1A
R–L
W–B

Y–G
R–L
(* 1)

R–L(*1)
Exhaust Gas Sensor

2 4 1
W–B DGS DGS1 SG

R–L
IG E
E12

3 6
W–B
R–L

29 1A 52 1A

14 1B 39 1B

R–L
W–B

W–B

W–B

23 2D 2 2D

IF EE

410
2004 LEXUS LX 470 (EWD546U)
 A47(A), A48(B), A49(C)
A/C Control Assembly

TAM FRTR FRSG FRAMC FRAMH FRTP FRTE

7 B 17 B 18 B 22 A 21 A 5 B 16 B

GR–B
Y–G
L–Y

P–G

P–B

B–Y
12 5B
G–R

Y–G

23 5D
2 3 5 4 6
MCOOL HMOT VZ PT GND
L–Y

G–R

Y–G
P–B

B–Y
P

32 1B
Warm

13 1A
Cool

GR–B
Room Temp. Sensor (Front)
L–Y

A/C Ambient Temp. Sensor

2 2 2
A26

A/C Thermistor
Air Mix Control Servo Motor

A19
R7
A1

1 1 1
Y–G

25 1A
G–R
Y–G

Y–G

Y–G

31 1B
Y–G

Y–G

2 3N 4 3N 1 3N

22 5D 13 5B 16 5B

14 5B 3 3N

Y–G

411
2004 LEXUS LX 470 (EWD546U)
Air Conditioning (Front)

A47(A), A48(B), A49(C)

A/C Control Assembly

TPI AIF AIR TS FRS5 TAMO2 MPX+ MPX– SPD RDFGR MRRHR RRMGV
14 B 1 A 2 A 8 B 9 B 1 C 19 A 39 A 6 C 10 A 6 A 40 A

B–Y

P–B
L–R

P–L
(* 2)

(* 1)

(* 1)
B

LG–R
LG

R
V
8 3N 28 3D 16 4A 10 4A 3 4C
LG–B
G–W

19 3N 83 3Q G–R 1 4E 6 4E 4 4E

Rear Cooler Magnetic Valve

DEFOG Relay

MIR HTR Relay

Combination Meter
P–B
(*1)

(*1)
SB

B
L–R

A/C Solar Sensor

3 4 5 2 4 11
PT MFRS MREC MPD1 MPD2

Gateway ECU
M
A18

P–L
(* 2)

G5
GTX+ GTX–
Air Inlet Control Servo Motor

5 12
SB

P–B
P–L
(* 1)

81 3Q 5 If2 4 If2 (* 1)
P–B
P–L
(*1)

(*1)
A25

GND VZ 16 11 12
1 2 30 3E A/C TX3+ TX3–
TEMP

M12 M6
Multi–Display Multi–Display
G–R

G–R

G–R
Y–G

13 3N 15 3N 7 3P 5 3N

412
2004 LEXUS LX 470 (EWD546U)
 * 1 : w/ LEXUS Navigation System From Power Source System (See Page 100)
A47(A), A48(B), A49(C) * 2 : w/o LEXUS Navigation System
A/C Control Assembly

10A 10A
ECU–B2 ECU–IG2
TC VER1 FRCID FRCLK FRCSD +B
3 C 18 C 10 B 1 B 2 B 11 C
W–B
W–L

L–W
71 3Q 19 3K 35 3K

B–W
L–W
SB
17 4A 10 4F 18 4A
(Shielded)

R
B

8 4A 2 4C 9 4A
W–B
W–L

L–W
26 3E 18 IS2 19 IS2 15 IS2 16 IS2 17 IS2
19 2E

21 3E
(Shielded)
W–B

22 2Q
W

R
B
W–L

SB

5
ACAN
J24(B), J27(A)

H A H A (* 1)
Connector

F B F B (* 2)
Junction

B9
Body ECU H A H A (* 1)
F B F B (* 2)
W–B

W–B

B–W
L–W
W

R
B

22 18 20 19 1 2
GND CID CLKF CSD +B IG

A33
A/C Amplifier
W–B

BK

413
2004 LEXUS LX 470 (EWD546U)
Air Conditioning (Front)
System Outline
1. Heater Blower Operation
Manual operation
When the blower speed is set ant any speed by the blower control SW, the A/C control assembly sends a signal to the
blower motor controller, and controls the blower motor speed.
Auto operation
When the auto SW is operated, the A/C control assembly sends signals to the blower motor controller, according to the
signals from respective sensors, commands from the temperature SW etc., and controls the blower motor automatically.
2. Air Inlet Control Servo Motor Control
When the FRESH/RECIRC select SW is switched to RECIRC, the motor in the air inlet control servo motor rotates to move
the damper to the RECIRC side. The damper position is recognized by the A/C control assembly TERMINAL TPI, and
rotates the motor until the damper reaches its position.
When the FRESH/RECIRC select SW is switched to FRESH, the motor in the air inlet control servo motor rotates to move
the damper to the FRESH side. The damper position is recognized by the A/C control assembly TERMINAL TPI, and rotates
the motor until the damper reaches its position.
When the FRESH/RECIRC select SW is set to auto, the exhaust gas sensor in the engine room detects the ingredient of the
exhaust emission, and switches the FRESH/RECIRC mode automatically.
3. Air Vent Mode Control Servo Motor
When the mode select SW in the A/C control assembly is pushed, a signal is sent from the A/C control assembly, and
activates the air vent mode control servo motor. This causes the servo motor to rotate to the position selected using the
mode select SW (FACE, BI–LEVEL, FOOT, FOOT/DEF, DEF), and moves the damper.
4. Air Mix Control Servo Motor
When the temperature control SW in the A/C control assembly is pushed, a signal is sent from the A/C control assembly, and
activates the air mix control servo motor. The motor and damper is moved until it reaches the temperature set by the
temperature control SW.
5. Air Conditioning Operation
The A/C control assembly receives various signals, i. e., the engine RPM from the crankshaft position sensor, outlet
temperature from the A/C ambient temp. sensor, coolant temperature from the engine coolant temp. sensor, and the lock
signal from the A/C compressor, etc. When the engine is started and the A/C SW is turned on, a signal is sent to the A/C
control assembly. As a result, the magnetic clutch is turned on and operates the compressor.
In addition, when the engine control module detects that the magnetic clutch is on and the A/C compressor is operating, it
controls the engine in the direction to avoid lowering the engine RPM during A/C operation.
When any of the following signals are sent to the A/C control assembly, the A/C is turned off.
∗ Coolant temp. is high.
∗ Outlet air temp. is low.
∗ Large difference between the engine speed and compressor speed.
∗ The refrigerant pressure is abnormally high or low.

Service Hints
A47 (A), A49 (C) A/C Control Assembly
(C)11–Ground : Always approx. 12 volts
(C)22–Ground : Approx. 12 volts with ignition SW at ON or ST position
(A)27–Ground : Approx. 12 volts with ignition SW at ON or ST position (w/o LEXUS navigation system)
(C)12, (C) 15, (C) 17, (C) 18–Ground : Always continuity
C34 Center Cluster Integration Panel (w/ LEXUS Navigation System)
2–Ground : Approx. 12 volts with ignition SW at ON or ST position
16–Ground : Always continuity

414
2004 LEXUS LX 470 (EWD546U)
 : Parts Location
Code See Page Code See Page Code See Page
A1 68 A47 A 70 E12 68
A4 68 A48 B 70 F19 68
A5 68 A49 C 70 G5 71
A18 70 B1 70 J14 72
A19 70 B9 70 J24 B 74
A25 70 C34 71 J27 A 74
A26 70 E6 C 71 M6 72
A27 70 E9 D 71 M12 72
A33 74 E10 E 71 R7 73

: Relay Blocks

Code See Page Relay Blocks (Relay Block Location)

1 22 Engine Room R/B (Engine Compartment Left)

: Junction Block and Wire Harness Connector

Code See Page Junction Block and Wire Harness (Connector Location)
1A 24 Engine Room Main Wire and Engine Room J/B (Engine Compartment Left)
1B 24 Engine Room No.2 Wire and Engine Room J/B (Engine Compartment Left)
2A 28 Engine Room No.2 Wire and Cowl Side J/B LH (Left Kick Panel)
2D
28 Dash Wire and Cowl Side J/B LH (Left Kick Panel)
2E
2Q 30 Instrument Panel Integration Wire and Cowl Side J/B LH (Left Kick Panel)
3D
3E 40 Dash Wire and Cowl Side J/B RH ((Right
g Kick Panel))
3H
3K 40 Floor No.2 Wire and Cowl Side J/B RH (Right Kick Panel)
3M
3N 43 Dash Wire and Cowl Side J/B RH ((Right
g Kick Panel))
3P
3Q 42 Instrument Panel Integration Wire and Cowl Side J/B RH (Right Kick Panel)
4A
4C
4D 52 Dash Wire and J/B No.4 ((Instrument Panel Center))
4E
4F
5A
56 Dash Wire and J/B No.5
No 5 (Behind the Combination Meter)
5B
5D 56 Engine Room No.2 Wire and J/B No.5 (Behind the Combination Meter)

: Connector Joining Wire Harness and Wire Harness

Code See Page Joining Wire Harness and Wire Harness (Connector Location)
IG1
82 Engine Room No.2
No 2 Wire and Dash Wire (Behind the Combination Meter)
IG5
IO3 82 Engine Wire and Dash Wire (Behind the Glove Box)
IS2 84 Dash Wire and Floor No.2 Wire (Right Kick Panel)
If2 88 Dash Wire and Dash Wire (Behind the Center Panel)

415
2004 LEXUS LX 470 (EWD546U)
Air Conditioning (Front)
: Ground Points

Code See Page Ground Points Location

EA 78 Front Right Side of Fender Apron
EC 78 Rear Bank of Right Cylinder Head
EE 78 Front Left Side of Fender Apron
IF 80 Set Bolt of Cowl Side J/B LH
II 80 Set Bolt of Cowl Side J/B RH
BK 90 Front Side Under the Front Passenger’s Seat

: Splice Points

Code See Page Wire Harness with Splice Points Code See Page Wire Harness with Splice Points
B9 92 Floor No.2 Wire

416
2004 LEXUS LX 470 (EWD546U)
 Memo

417
2004 LEXUS LX 470 (EWD546U)