Infiniti Q45. Manual - part 122

TROUBLE DIAGNOSIS

ATC-83

ATC

Blower Speed Compensation

Sunload
When the in-vehicle temperature and the set temperature are very close, the blower will be operating at low
speed. The low speed will vary depending on the sunload. During conditions of low or no sunload, the blower
speed is at duty ratio 25%. During high sunload conditions, the auto amp. raise the blower fan speed to
increase.(duty ratio 49%).

Fan Speed Control Specification

COMPONENT DESCRIPTION
Brush-Less Motor

The blower motor utilizes a brush-less motor with a rotating magnet.
Quietness is improved over previous motors where the brush was
the point of contact and the coil rotated.

DIAGNOSIS PROCEDURE FOR BLOWER MOTOR

SYMPTOM: Blower motor operation is malfunctioning.

RJIA1907E

ZHA152H

RJIA0267E

ATC-84

TROUBLE DIAGNOSIS

CHECK POWER SUPPLY FOR BLOWER MOTOR

Disconnect blower motor connector.

Turn ignition switch ON.

Check voltage between blower motor harness connector M112
terminal 4 and ground.

OK or NG

>> GO TO 2.

>> Check power supply circuit and 15 A fuses [Nos. 31 and

33, located in the fuse block (J/B) No. 2]. Refer to

PG-

71, "FUSE BLOCK - JUNCTION BOX (J/B) NO. 2"

●

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

●

If fuse are NG, replace fuse and check harness for short circuit. Repair or replace if necessary.

CHECK GROUND CIRCUIT FOR BLOWER MOTOR

Turn ignition switch OFF.

Check continuity between blower motor harness connector
M112 terminal 1 and ground.

OK or NG

>> GO TO 3.

>> Repair harness or connector.

CHECK CIRCUIT CONTINUITY BLOWER MOTOR AND AUTO AMP.

Disconnect auto amp. connector.

Check continuity between blower motor harness connector
M112 terminal 3 and auto amp. harness connector M120 termi-
nal 35.

OK or NG

>> GO TO 4.

>> Repair harness or connector.

4 – Ground

: Battery voltage

RJIA3031E

1 – Ground

: Continuity should exist.

RJIA3032E

3 – 35

: Continuity should exist.

RJIA3033E

TROUBLE DIAGNOSIS

ATC-85

ATC

CHECK FOR AUTO AMP. OUTPUT

Reconnect blower motor connector and check connector.

Turn ignition switch ON.

Change the fan speed from Lo to Hi, and check the duty ratios
between blower motor harness connector M112 terminal 3 and
ground by using an oscilloscope. Normal terminal 3 drive signal
duty ratios are shown in the table below.

OK or NG

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

>> Replace auto amp.

COMPONENT INSPECTION
Blower Motor

Confirm smooth rotation of the blower motor.

●

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

RJIA3034E

RJIA0338E

RJIA0271E