Page 3353 of 3833
TROUBLE DIAGNOSIS
ATC-77
C
D
E
F
G
H
I
K
L
MA
B
AT C
9.CHECK CIRCUIT CONTINUITY BETWEEN AUTO AMP. AND FAN CONTROL AMP.
OK or NG
OK >> Replace auto amp.
NG >> Repair harness or connector.
COMPONENT INSPECTION
Blower Motor
Confirm smooth rotation of the blower motor.
●Ensure that there are no foreign particles inside the intake unit.
Te r m i n a l s
Continuity Auto amp. Fan control amp.
ConnectorTerminal
(Wire color)ConnectorTerminal
(Wire color)
M52 18 (R) M67 3 (R) Yes
RJIA0531E
RJIA0532E
Page 3354 of 3833
ATC-78
TROUBLE DIAGNOSIS
Magnet Clutch Circuit
EJS001H5
SYMPTOM: Magnet clutch does not engage.
INSPECTION FLOW
*1AT C - 4 7 , "PROCEDURE", see No. 1. *2ATC-100, "Ambient Sensor Circuit".*3ATC-102, "In-vehicle Sensor Cir-
cuit".
*4ATC-105, "
Sunload Sensor Circuit".*5ATC-64, "Air Mix Door Motor Circuit".*6ATC-47, "PROCEDURE", see No.
14.
*7AT C - 7 8 , "
Magnet Clutch Circuit".*8ATC-92, "TROUBLE DIAGNOSES
FOR UNUSUAL PRESSURE".*9ATC-54, "
Operational Check".
*10AT C - 4 7 , "
PROCEDURE", see No. 5
to 7.*11ATC-54, "Operational Check".*12ATC-33, "SYMPTOM TABLE".
*13ATC-108, "
Intake Sensor Circuit".
RJIA0533E
Page 3355 of 3833
TROUBLE DIAGNOSIS
ATC-79
C
D
E
F
G
H
I
K
L
MA
B
AT C
SYSTEM DESCRIPTION
Auto amplifier controls compressor operation by ambient temperature and signal from ECM.
Low Temperature Protection Control (With Gasoline Engine)
Auto amplifier will turn the compressor ON or OFF as determined by
a signal detected by ambient sensor.
When ambient temperatures are greater than -2°C, the compressor
turns ON. The compressor turns OFF when ambient temperatures
are less than -5°C.
Evaporator Freeze Protection Control (With Diesel Engine)
Auto amplifier will turn the compressor ON or OFF as determined by
a signal detected by intake sensor.
When intake temperatures are greater than 4°C, the compressor
turns ON. The compressor turns OFF when intake temperatures are
less than 2.5°C.
DIAGNOSTIC PROCEDURE
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
RHA094GB
RJIA0534E
RJIA0535E
Page 3356 of 3833

ATC-80
TROUBLE DIAGNOSIS
1. CHECK POWER SUPPLY FOR COMPRESSOR
Disconnect compressor harness connector.
OK or NG
OK >> Check magnet clutch coil.
1. If NG, replace magnet clutch. Refer to ATC-135,
"Removal and Installation for Compressor Clutch" .
2. Go to self-diagnosis AT C - 4 7 , "
PROCEDURE" and perform self-diagnosis STEP-4. Confirm
that magnet clutch operation is normal.
NG >> Disconnect A/C relay. And GO TO 2.
2. CHECK CIRCUIT CONTINUITY BETWEEN A/C RELAY AND COMPRESSOR
OK or NG
OK >> Check harness for short. And GO TO 3.
NG >> Repair harness or connector.
3. CHECK POWER SUPPLY FOR A/C RELAY
Disconnect A/C relay.
OK or NG
OK >> GO TO 4.
NG >> Check power supply circuit and 10A fuse [No.15 located
in the fuse block (J/B)]. Refer to PG-3, "
BATTERY POWER SUPPLY — IGNITION SW. IN ANY
POSITION" .
●If OK, check for open circuit in wiring harness. Repair or replace as necessary.
●If NG, replace fuse and check wiring harness for short circuit. Repair or replace as necessary.
Te r m i n a l s
Voltag e (+)
(-)
ConnectorTe r m i n a l ( W i r e
color
E34 1 (L/R) Ground Battery voltage
RJIA0295E
Terminals
Continuity A/C relay Compressor
ConnectorTerminal
(Wire color)ConnectorTerminal
(Wire color)
E5 5 (L/R) E34 1 (L/R) Yes
RJIA0536E
Te r m i n a l s
Voltage (+)
(-)
ConnectorTe r m i n a l ( W i r e
color)
E5 1 (BR/Y)
Ground Battery voltage
E5 3 (BR/Y)
RJIA0537E
Page 3357 of 3833

TROUBLE DIAGNOSIS
ATC-81
C
D
E
F
G
H
I
K
L
MA
B
AT C
4.CHECK A/C RELAY AFTER DISCONNECTING IT
Refer to ATC-84, "
A/C Relay" .
OK or NG
OK >> Reconnect A/C relay. And GO TO 5.
NG >> 1. replace A/C relay.
2. Go to self-diagnosis AT C - 4 7 , "
PROCEDURE" and perform self-diagnosis STEP-4.Confirm that
magnet clutch operation is normal.
5.CHECK COIL SIDE CIRCUIT OF A/C RELAY
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector.
6.CHECK AMBIENT SENSOR
Refer to ATC-100, "
Ambient Sensor Circuit" .
OK or NG
OK >>●With gasoline engine: GO TO 7.
●With diesel engine: GO TO 14.
NG >> Repair or replace the malfunctioning part(s).
7.CHECK REFRIGERANT PRESSURE SENSOR (QR ENGINE)
Refer to ATC-85, "
Refrigerant Pressure Sensor (With Gasoline Engine)" .
OK or NG
OK >> GO TO 8.
NG >> Repair or replace the malfunctioning part(s).
8.CHECK VOLTAGE FOR AUTO AMP. (COMPRESSOR ON SIGNAL)
OK or NG
OK >> GO TO 9.
NG >>
●If the voltage is approx. 4.8V when the A/C switch is
ON: Replace the auto amp.
●If the voltage is approx. 0V when the A/C switch is OFF: GO TO 12.
Engine modelsTerminals
Voltag e (+)
(-)
ConnectorTerminal
(Wire color)
With gasoline
engineF43 26 (L)
Ground Battery voltage
With diesel
engineF34 D11 (I)
RJIA1946E
Terminals
Condition Voltage
(+) (-)
ConnectorTe r m i n a l ( W i r e
color)
GroundA/C SW: ON Approx. 0V
M52 4 (L/R) A/C SW: OFF Approx. 4.8V
RJIA0539E
Page 3358 of 3833

ATC-82
TROUBLE DIAGNOSIS
9. CHECK VOLTAGE FOR AUTO AMP. (COMPRESSOR FEED BACK SIGNAL)
OK or NG
OK >> GO TO 10.
NG >> GO TO 13.
10. CHECK VOLTAGE FOR AUTO AMP. (FAN ON SIGNAL)
OK or NG
OK >> Replace auto amp.
NG >>
●If the voltage is approx. 4.8 V when the blower fan is
ON: Replace the auto amp.
●If the voltage is approx. 0 V when the blower fan is OFF: GO TO 11.
11 . CHECK CIRCUIT CONTINUITY BETWEEN ECM AND AUTO AMP.
Disconnect ECM connector and auto amp. connector.
OK or NG
OK >> INSPECTION END.
NG >> Repair harness or connector.
Terminals
Condition Voltage (+)
(-)
ConnectorTerminal
(Wire color)
M53 30 (PU) GroundA/C SW: ON Approx. 0V
A/C SW: ON
(Disconnect
refrigerant pres-
sure sensor con-
nector)Approx. 4.8V
RJIA0540E
Terminals
Condition Voltage (+)
(-)
ConnectorTerminal
(Wire color)
M52 19 (LG/B) GroundBlower fan: ON Approx. 0V
Blower fan: OFF Approx. 4.8V
RJIA0541E
terminals
Continuity ECM Auto amp.
ConnectorTerminal (Wire
coor)ConnectorTerminal (Wire
color)
F43 55 (LG/B) M52 19 (LG/B) Yes
RJIA0542E
Page 3359 of 3833

TROUBLE DIAGNOSIS
ATC-83
C
D
E
F
G
H
I
K
L
MA
B
AT C
12.CHECK CIRCUIT CONTINUITY BETWEEN ECM AND AUTO AMP. (QR ENGINE)
Disconnect ECM connector and auto amp. connector.
OK or NG
OK >> Check EC-412, "REFRIGERANT PRESSURE SEN-
SOR" for QR25 engine (WITH EURO-OBD), EC-733,
"REFRIGERANT PRESSURE SENSOR" for QR25
engine (WITHOUT EURO-OBD), EC-1099, "
REFRIGERANT PRESSURE SENSOR" for QR20
engine (WITH EURO-OBD), and EC-1373, "
REFRIGERANT PRESSURE SENSOR" for QR20
engine (WITHOUT EURO-OBD) in ECM.
NG >> Repair harness or connector.
13.CHECK CIRCUIT CONTINUITY BETWEEN ECM AND AUTO AMP. (QR ENGINE)
Disconnect ECM connector and auto amp. connector.
OK or NG
OK >> Check EC-412, "REFRIGERANT PRESSURE SEN-
SOR" for QR25 engine (WITH EURO-OBD), EC-733,
"REFRIGERANT PRESSURE SENSOR" for QR25
engine (WITHOUT EURO-OBD), EC-1099, "
REFRIGERANT PRESSURE SENSOR" for QR20
engine (WITH EURO-OBD), and EC-1373, "
REFRIGERANT PRESSURE SENSOR" for QR20
engine (WITHOUT EURO-OBD) in ECM.
NG >> Repair harness or connector.
14.CHECK VOLTAGE FOR AUTO AMP. (COMPRESSOR ON SIGNAL)
OK or NG
OK >> INSPECTION END.
NG >> GO TO 15.
Te r m i n a l s
Continuity ECM Auto amp.
ConnectorTerminal (Wire
color)ConnectorTerminal (Wire
color)
F43 44 (L/R) M52 4 (L/R) Yes
RJIA1947E
Te r m i n a l s
Continuity ECM connector Auto amp. connector
ConnectorTerminal (Wire
color)ConnectorTerminal (Wire
color)
F43 30 (PU/W) M53 30 (PU/W) Yes
RJIA0544E
Terminals
Condition Voltage (+)
(-)
ConnectorTerminal
(Wire color)
M52 4 (L/R) GroundA/C SW: ON Approx. 0V
A/C SW: OFFApprox.
4.8V
RJIA0539E
Page 3360 of 3833

ATC-84
TROUBLE DIAGNOSIS
15. CHECK DUAL- PRESSURE SWITCH (YD ENGINE)
Refer to AT C - 8 5 , "
Dual-Pressure Switch (With Diesel Engine)" .
OK or NG
OK >> GO TO 16.
NG >> Replace the dual-pressure switch.
16. CHECK CIRCUIT CONTINUITY BETWEEN AUTO AMP. AND DUAL-PRESSURE SWITCH
Disconnect the auto amp. connector.
OK or NG
OK >> GO TO 17.
NG >> Repair harness or connector.
17. CHECK CIRCUIT CONTINUITY BETWEEN DUAL-PRESSURE SWITCH AND ECM
Disconnect the ECM connector.
OK or NG
OK >> Check EC-1572, "AIR CONDITIONER CONTROL" in
ECM.
NG >> Repair harness or connector.
COMPONENT INSPECTION
A/C Relay
Check continuity between terminal Nos. 3 and 5.
If NG, replace relay.
Terminals
Continuity Auto amp. Dual-pressure switch
ConnectorTerminal (Wire
color)ConnectorTerminal (Wire
color)
M52 4 (L/R) E40 2 (L/R) Yes
RJIA0545E
Terminals
Continuity Dual-pressure switch connector ECM connector
ConnectorTe r m i n a l ( W i r e
color)ConnectorTerminal (Wire
color)
E40 1 (PU/W) F34 D23 (PU/W) Yes
RJIA0546E
Conditions Continuity
12V direct current supply between terminal Nos. 1
and 2Ye s
No current supply No
RHA638H
SMA for models with roof
mounted drivin
g lamp