Infiniti G37 Coupe. Manual — part 769

MAGNET CLUTCH CONTROL SYSTEM

HAC-65

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

C

D

E

F

G

H

J

K

L

M

A

B

HAC

N

O

P

MAGNET CLUTCH CONTROL SYSTEM

System Diagram

INFOID:0000000001734543

System Description

INFOID:0000000001734544

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

SYSTEM OPERATION

When A/C switch, AUTO switch, DEF switch or D/F switch is pressed, unified meter and A/C amp. transmits
compressor ON signal to ECM, via CAN communication.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant-pressure sen-
sor signal, throttle angle, etc.). If it judges compressor can be turned ON, it sends compressor ON signal to
IPDM E/R, via CAN communication.
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate com-
pressor.
When sending compressor ON signal to IPDM E/R via CAN communication line, ECM simultaneously sends
compressor feedback signal to ECM via CAN communication line.
ECM sends compressor feedback signal to unified meter and A/C amp., then, uses input compressor feed-
back signal to control air inlet.

Compressor Protection Control

When the high-pressure side detected by the refrigerant pressure sensor is either approximately 3,119 kPa
(31.8 kg/cm

2

, 452 psi) or more, or approximately 118 kPa (1.2 kg/cm

2

, 17 psi) or less, ECM turns the A/C relay

OFF and stops the compressor.

Low Temperature Protection Control

Unified meter and A/C amp. turns compressor ON or OFF as judged 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).

JSIIA0781GB

RHA094GB

HAC-66

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

MAGNET CLUTCH CONTROL SYSTEM

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).

SJIA0267E

MODE DOOR MOTOR

HAC-67

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

C

D

E

F

G

H

J

K

L

M

A

B

HAC

N

O

P

COMPONENT DIAGNOSIS

MODE DOOR MOTOR

Description

INFOID:0000000001675693

COMPONENT DESCRIPTION

Mode Door Motor

The mode door motor (1) are attached to the heater & cooling unit
assembly. It rotates so that air is discharged from the outlet set by
the unified meter and A/C amp. Motor rotation is conveyed to a link
which activates the mode door.

Component Function Check

INFOID:0000000001675694

1.

CONFIRM SYMPTOM BY PERFORMING THE FOLLOWING OPERATIONAL CHECK

1.

Press MODE switch(es) and DEF switch.

2.

Each position indicator should change shape.

3.

Confirm that discharge air comes out according to the air distribution table at below. Refer to

HAC-23,

"WITHOUT LEFT AND RIGHT VENTILATION TEMPERATURE SEPARATELY CONTROL SYSTEM :
System Description"

(Without left and right ventilation temperature separately control system) or

HAC-32,

"WITH LEFT AND RIGHT VENTILATION TEMPERATURE SEPARATELY CONTROL SYSTEM : System
Description"

(With left and right ventilation temperature separately control system).

NOTE:
Confirm that the compressor clutch is engaged (Sound or visual inspection) and intake door position is at FRE
when DEF

or D/F

is selected.

Is the inspection result normal?

YES

>> END.

NO

>> Go to diagnosis procedure. Refer to

HAC-67, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000001675695

1.

PERFORM SELF-DIAGNOSIS STEP-2

Perform self-diagnosis STEP-2. Refer to

HAC-42, "WITHOUT LEFT AND RIGHT VENTILATION TEMPERA-

TURE SEPARATELY CONTROL SYSTEM : Diagnosis Description"

(Without left and right ventilation tempera-

ture separately control system) or

HAC-48, "WITH LEFT AND RIGHT VENTILATION TEMPERATURE

SEPARATELY CONTROL SYSTEM : Diagnosis Description"

(With left and right ventilation temperature sepa-

rately control system), see Nos. 1 to 2.

Does code No. 20 appear on the display?

YES

>> GO TO 2.

NO

>> Go to appropriate malfunctioning sensor circuit. Refer to

HAC-42, "WITHOUT LEFT AND RIGHT

VENTILATION TEMPERATURE SEPARATELY CONTROL SYSTEM : Diagnosis Description"

(Without left and right ventilation temperature separately control system) or

HAC-48, "WITH LEFT

AND RIGHT VENTILATION TEMPERATURE SEPARATELY CONTROL SYSTEM : Diagnosis
Description"

(With left and right ventilation temperature separately control system), see No. 11.

2.

PERFORM SELF-DIAGNOSIS STEP-3

Perform self-diagnosis STEP-3. Refer to

HAC-42, "WITHOUT LEFT AND RIGHT VENTILATION TEMPERA-

TURE SEPARATELY CONTROL SYSTEM : Diagnosis Description"

(Without left and right ventilation tempera-

ture separately control system)

HAC-48, "WITH LEFT AND RIGHT VENTILATION TEMPERATURE

:

Vehicle front

JSIIA0005GB

HAC-68

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

MODE DOOR MOTOR

SEPARATELY CONTROL SYSTEM : Diagnosis Description"

(With left and right ventilation temperature sepa-

rately control system), see Nos. 1 to 3.
Does code No. 30 appear on the display?

YES

>> GO TO 6.

NO-1

>> Code No. 31 or 32 appear on the display: GO TO 3.

NO-2

>> Code No. 37, 38 or 39 appear on the display: Go to Intake Door Motor Circuit. Refer to

HAC-75,

"Diagnosis Procedure"

.

3.

CHECK POWER SUPPLY FOR MODE DOOR MOTOR

Check voltage between mode door motor harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair harness or connector.

4.

CHECK SIGNAL FOR MODE DOOR MOTOR

Confirm A/C LAN signal between mode door motor harness connector and ground using an oscilloscope.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair harness or connector.

5.

CHECK MODE DOOR MOTOR GROUND CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect mode door motor connector.

3.

Check continuity between mode door motor harness connector and ground.

Is the inspection result normal?

YES

>> Replace mode door motor.

NO

>> Repair harness or connector.

6.

PERFORM SELF-DIAGNOSIS STEP-4

Perform self-diagnosis STEP-4. Refer to

HAC-42, "WITHOUT LEFT AND RIGHT VENTILATION TEMPERA-

TURE SEPARATELY CONTROL SYSTEM : Diagnosis Description"

(Without left and right ventilation tempera-

ture separately control system)

HAC-48, "WITH LEFT AND RIGHT VENTILATION TEMPERATURE

SEPARATELY CONTROL SYSTEM : Diagnosis Description"

(With left and right ventilation temperature sepa-

rately control system), see Nos. 1 to 5.

(+)

(

−

)

Voltage

Mode door motor

—

Connector

Terminal

M253

1

Ground

Battery voltage

(+)

(

−

)

Voltage

Mode door motor

—

Connector

Terminal

M253

3

Ground

SJIA1453J

Mode door motor

—

Continuity

Connector

Terminal

M253

2

Ground

Existed