Page 505 of 3419
ATC-110
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
COMPONENT INSPECTION
Rear Blower Motor Relay
Check circuit continuity between terminals 3 and 5 by supplying 12
volts and ground to coil side terminals 1 and 2 of relays.
Rear Blower Switch (Rear)
Check continuity between terminals at each switch position.
Rear Blower Switch (Front)
Check continuity between terminals at each switch position.
WJIA2003E
LJ IA0113E
LJ IA0114E
Page 506 of 3419
TROUBLE DIAGNOSIS
ATC-111
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: October 20052005 QX56
Rear Blower Motor
Check that there are no foreign particles inside the intake unit.
Apply 12 volts to terminal 2 and ground to terminal 1 and ensure that
the blower motor rotates freely and quietly.
Rear Blower Motor Resistor
Check continuity between terminals. There will be resistance, but
there should not be an open or short between any two terminals.
WJIA1268E
WJIA1269E
Page 507 of 3419
ATC-112
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Rear Air Control CircuitEJS003XU
SYMPTOM:
Temperature cannot be adjusted from the rear air control.
INSPECTION FLOW
*1AT C - 6 0 , "Operational Check
(Rear)"AT C - 6 0 , "Operational Check
(Rear)"
*2AT C - 5 5 , "A/C System Self-diagno-
sis Function"
*3AT C - 5 6 , "SELF-DIAGNOSIS CODE
CHART"
*4AT C - 11 3 , "DIAGNOSTIC PROCE-
DURE FOR REAR AIR CONTROL"
*5AT C - 7 9 , "DIAGNOSTIC PROCE-
DURE FOR AIR MIX DOOR
MOTOR (REAR)"
WJIA1270E
Page 508 of 3419

TROUBLE DIAGNOSIS
ATC-113
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: October 20052005 QX56
SYSTEM DESCRIPTION
Component Parts
Rear air control system components are:
Front air control
Rear air control
Air mix door motor (rear)
Rear blower motor relay
Rear blower motor resistor
Rear blower motor
System Operation
Rear Air Control
When the rear blower switch (front) (integral to the front air control) is in the REAR position the rear blower
motor speeds and the rear temperature and mode are controlled by the rear blower switch (rear) and the rear
temperature switch (rear) (both integral to the rear air control).
DIAGNOSTIC PROCEDURE FOR REAR AIR CONTROL
SYMPTOM:
Blower motor operation is malfunctioning. Refer to ATC-101, "Rear Blower Motor Circuit" .
Temperature and mode operation is malfunctioning.
1. CHECK OPERATION FROM FRONT AIR CONTROL
Does rear temperature and mode operate normally from front air control?
YES or NO
YES >> GO TO 2.
NO >> Refer to ATC-79, "
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (REAR)" .
WJIA1132E
Page 509 of 3419

ATC-114
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
2. CHECK CIRCUIT BETWEEN REAR AIR CONTROL AND FRONT AIR CONTROL FOR OPEN AND
SHORT
1. Turn ignition switch OFF.
2. Disconnect front air control and rear air control connectors.
3. Check continuity between front air control harness connector
M50 terminal 33 (V) and rear air control harness connector
R209 terminal 5 (V).
4. Check continuity between rear air control harness connector
R209 terminal 5 (V) and ground.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
3. CHECK CIRCUIT BETWEEN REAR AIR CONTROL AND AIR MIX DOOR MOTOR (REAR) FOR OPEN
OR SHORT
1. Disconnect air mix door motor (rear) connector.
2. Check continuity between rear air control harness connector
R209 terminal 2 (P) and 4 (Y) and air mix door motor (rear) har-
ness connector B155 terminal 2 (P) and 3 (Y).
3. Check continuity between rear air control harness connector
R209 terminals 2 (P) and 4 (Y) and ground.
OK or NG
OK >> Replace rear air control.
NG >> Repair harness or connector.33 - 5 Continuity should exist.
5 - Ground Continuity should not exist.
WJIA1441E
2 - 2 Continuity should exist.
4 - 3 Continuity should exist.
2, 4 - Ground Continuity should not exist.
WJIA1442E
Page 510 of 3419
TROUBLE DIAGNOSIS
ATC-115
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: October 20052005 QX56
Magnet Clutch CircuitEJS003XV
SYMPTOM: Magnet clutch does not engage.
INSPECTION FLOW
*1ATC-57, "Operational Check (Front)"*2AT C - 5 5 , "A/C System Self-diagnosis
Function"
*3AT C - 5 6 , "SELF-DIAGNOSIS CODE
CHART"
*4ATC-137, "Ambient Sensor Circuit"*5ATC-145, "Intake Sensor Circuit"
WJIA1285E
Page 511 of 3419

ATC-116
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
SYSTEM DESCRIPTION
The front air control controls compressor operation based on ambient and intake temperature and a signal
from ECM.
Low Temperature Protection Control
The front air control will turn the compressor ON or OFF as determined by a signal detected by the intake sen-
sor and the ambient sensor.
When intake air temperature is higher than the preset value, the compressor turns ON. The compressor turns
OFF when intake air temperature is lower than the preset value. That preset value is dependent on the ambi-
ent temperature, refer to the following table.
DIAGNOSTIC PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
1. CHECK INTAKE AND AMBIENT SENSOR CIRCUITS
Check intake and ambient sensors. Refer to ATC-55, "
A/C System Self-diagnosis Function" .
OK or NG
OK >> GO TO 2.
NG >>
Malfunctioning intake sensor. Refer to ATC-145, "Intake Sensor Circuit" .
Malfunctioning ambient sensor. Refer to ATC-145, "Intake Sensor Circuit" .
Ambient temperature °C (°F)C om pr e ss o r O N
intake temperature °C (°F)C o m p r e s s o r O F F
intake temperature °C (°F)
0 (32) 2.5 (37) 2.0 (36)
10 (50) 2.5 (37) 2.0 (36)
20 (68) 2.5 (37) 1.5 (35)
30 (86) 2.0 (36) 0.5 (33)
40 (104) 2.0 (36) 0.5 (33)
50 (122) 2.0 (36) 0.5 (33)
WJIA1369E
Page 512 of 3419

TROUBLE DIAGNOSIS
ATC-117
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: October 20052005 QX56
2. PERFORM AUTO ACTIVE TEST
Refer to PG-22, "
Auto Active Test" .
Does magnet clutch operate?
YES or NO
YES >>WITH CONSULT-II
GO TO 5.
WITHOUT CONSULT-II
GO TO 6.
NO >> Check 10A fuse (No. 42, located in IPDM E/R), and GO TO 3.
3. CHECK CIRCUIT CONTINUITY BETWEEN IPDM E/R AND COMPRESSOR
1. Turn ignition switch OFF.
2. Disconnect IPDM E/R connector and compressor (magnet
clutch) connector.
3. Check continuity between IPDM E/R harness connector E119
terminal 11 (Y/B) and compressor harness connector F3 termi-
nal 1 (Y/B).
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK MAGNET CLUTCH CIRCUIT
Check for operation sound when applying battery voltage direct cur-
rent to terminal.
OK or NG
OK >> Replace IPDM E/R. Refer to PG-28, "Removal and
Installation of IPDM E/R" .
NG >> Replace magnet clutch. Refer to ATC-180, "
Removal
and Installation for Compressor Clutch" .
5. CHECK BCM INPUT (COMPRESSOR ON) SIGNAL
Check compressor ON/OFF signal. Refer to ATC-33, "
CONSULT-II
Function (HVAC)" .
OK or NG
OK >> GO TO 8.
NG >> GO TO 6.
11 – 1 : Continuity should exist.
WJIA0560E
SJIA0197E
A/C SW ON : COMP ON SIG ON
A/C SW OFF : COMP ON SIG OFF
WJIA0469E