Infiniti M35/M45 Y50. Manual — part 135

TROUBLE DIAGNOSIS

ATC-91

C

D

E

F

G

H

I

K

L

M

A

B

ATC

1.

CHECK POWER SUPPLY FOR BLOWER MOTOR

1.

Disconnect blower motor connector.

2.

Turn ignition switch ON.

3.

Check voltage between blower motor harness connector M91
terminal 1 and ground.

OK or NG

OK

>> GO TO 2.

NG

>> Check power supply circuit and 15A fuses [Nos. 10 and

11, located in the fuse block (J/B)]. Refer to

PG-114,

"FUSE BLOCK - JUNCTION BOX (J/B)"

.

●

If fuses are OK, check harness for open circuit. Repair or replace if necessary.

●

If fuses are NG, check harness for short circuit and replace fuse.

2.

CHECK BLOWER MOTOR GROUND CIRCUIT

1.

Turn ignition switch OFF.

2.

Check continuity between blower motor harness connector M91
terminal 3 and ground.

OK or NG

OK

>> GO TO 3.

NG

>> Repair harness or connector.

3.

CHECK CIRCUIT CONTINUITY BETWEEN BLOWER MOTOR AND UNIFIED METER AND A/C AMP.

1.

Disconnect unified meter and A/C amp. connector.

2.

Check continuity between blower motor harness connector M91
terminal 2 and unified meter and A/C amp. harness connector
M64 terminal 38.

OK or NG

OK

>> GO TO 4.

NG

>> Repair harness or connector.

1 – Ground

: Battery voltage

RJIA1997E

3 – Ground

: Continuity should exist.

RJIA4072E

2 – 38

: Continuity should exist.

RJIA4073E

ATC-92

TROUBLE DIAGNOSIS

4.

CHECK UNIFIED METER AND A/C AMP. OUTPUT SIGNAL

1.

Reconnect blower motor connector and unified meter and A/C
amp. connector.

2.

Turn ignition switch ON.

3.

Set MODE switch to VENT position.

4.

Change the fan speed from Lo to Hi, and check the duty ratios
between blower motor harness connector M91 terminal 2 and
ground by using an oscilloscope. Normal terminal 2 drive signal
duty ratios are shown in the table below.

OK or NG

OK

>> Replace blower motor after confirming the fan air flow does not change.

NG

>> Replace unified meter and A/C amp.

COMPONENT INSPECTION
Blower Motor

Confirm smooth rotation of the blower motor.

●

Ensure that there are no foreign particles inside the blower unit.

RJIA4074E

RJIA4075E

RJIA4076E

TROUBLE DIAGNOSIS

ATC-93

C

D

E

F

G

H

I

K

L

M

A

B

ATC

Magnet Clutch Circuit

NJS000GU

SYMPTOM: Magnet clutch does not engage.

INSPECTION FLOW

*1

ATC-121, "Intake Sensor Circuit"

*2

ATC-112, "Ambient Sensor Circuit"

*3

ATC-57, "FUNCTION CONFIRMA-
TION PROCEDURE"

, see No. 13.

*4

ATC-94, "DIAGNOSIS PROCE-
DURE FOR MAGNET CLUTCH"

*5

ATC-104, "TROUBLE DIAGNOSIS
FOR UNUSUAL PRESSURE"

*6

ATC-65, "Operational Check"

*7

ATC-57, "FUNCTION CONFIRMA-
TION PROCEDURE"

, see No. 2 to 6.

*8

ATC-41, "SYMPTOM TABLE"

RJIA4077E

ATC-94

TROUBLE DIAGNOSIS

SYSTEM DESCRIPTION

Unified meter and A/C amp. controls compressor operation by ambient temperature, intake air temperature
and signal from ECM.

Low Temperature Protection Control

Unified meter and A/C amp. will turn compressor ON or OFF as determined by a signal detected by ambient
sensor and intake sensor.
When ambient temperature is higher than

−

2

°

C (28

°

F), the compres-

sor turns ON. The compressor turns OFF when ambient temperature
is lower than

−

5

°

C (23

°

F).

When intake air temperature is higher than 1

°

C (34

°

F), the compres-

sor turns ON. The compressor turns OFF when intake air tempera-
ture is lower than

−

5

°

C (23

°

F).

DIAGNOSIS PROCEDURE FOR MAGNET CLUTCH

SYMPTOM: Magnet clutch does not engage when A/C switch is ON.

RHA094GB

SJIA0267E

RJIA4078E