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Nissan Pathfinder (2008 year). Manual - part 437

HAC-40

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

AIR MIX DOOR MOTOR

Turn ignition switch OFF.

Disconnect A/C auto amp. harness connector.

Check continuity between A/C auto amp. harness connector
M50 terminal 29 and ground.

Is the inspection result normal?

YES

>> Replace A/C auto amp. Refer to

VTL-8, "Removal and

Installation"

>> Repair or replace harness as necessary.

12.

CHECK PBR FEEDBACK CIRCUIT FOR OPEN

Turn ignition switch OFF.

Disconnect the air mix door motor (passenger) harness connec-
tor and A/C auto amp. harness connector.

Check continuity between air mix door motor (passenger) har-
ness connector M143 terminal 2 and A/C auto amp. harness
connector M50 terminal 29.

Is the inspection result normal?

YES

>> Replace air mix door motor (passenger). Refer to

VTL-

29, "Removal and Installation"

>> Repair or replace harness as necessary.

Continuity should not exist.

AWIIA0132ZZ

Continuity should exist.

AWIIA0233ZZ

INTAKE DOOR MOTOR

HAC-41

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

HAC

INTAKE DOOR MOTOR

System Description

INFOID:0000000001366708

SYSTEM DESCRIPTION

SYMTOM:

• Intake door motor does not operate normally.
• Intake door does not change.

SYSTEM DESCRIPTION

Component Parts

Intake door control system components are:

• A/C auto amp.
• A/C and AV switch assembly
• Intake door motor (PRB built into the intake door motor)
• In-vehicle sensor
• Ambient sensor
• Optical sensor
• Intake sensor

System Operation

The intake door control determines the intake door position based on the position of the recirculation switch.
When the recirculation switch is depressed the intake door motor rotates closing off the fresh air inlet and
recirculating the cabin air. If the recirculation switch is depressed again, the intake door motor rotates in the
opposite direction, again allowing fresh air into the cabin.
In the AUTO mode, the A/C auto amp. determines the intake door position based on the ambient temperature,
the intake air temperature and the in-vehicle temperature. When the DEF, D/F, FLOOR or OFF switches are
pushed, the A/C auto amp. sets the intake door at the fresh position.

Intake Door Control Specification

AWIIA0144GB

AWIIA0145GB

HAC-42

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

INTAKE DOOR MOTOR

COMPONENT DESCRIPTION

Intake door motor

The intake door motor is attached to the intake unit. It rotates so that
air is drawn from inlets set by the A/C auto amp. Motor rotation is
conveyed to a lever which activates the intake door.

Intake Door Motor Component Function Check

INFOID:0000000001366709

INSPECTION FLOW

CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - REC (

)

Press the mode switch to vent mode(

Press REC (

) switch. The REC (

)indicator should illuminate.

Press REC (

) switch again. The REC (

) indicator should go out.

Listen for intake door position change (you should hear blower sound changes slightly).

Can a symptom be duplicated?

YES

>> GO TO 3.

>> GO TO 2.

PERFORM COMPLETE OPERATIONAL CHECK

Perform a complete operational check and check for any symptoms. Refer to

HAC-123, "Operational Check"

Can a symptom be duplicated?

YES

>> Refer to

HAC-122, "How to Perform Trouble Diagnosis For Quick And Accurate Repair"

>> System OK.

CHECK FOR SERVICE BULLETINS

Check for any service bulletins.

>> GO TO 4.

CHECK INTAKE DOOR OPERATION

Check and verify intake door mechanism for smooth operation.
Is the inspection result normal?

YES

>> GO TO 5.

>> Repair intake door mechanism.

PERFORM SELF-DIAGNOSIS

Perform self-diagnosis to check for any codes. Refer to

HAC-23, "A/C Auto Amp. Self-Diagnosis"

Are any self-diagnosis codes present?

YES

>> Refer to

HAC-24, "A/C System Self-Diagnosis Code Chart"

>> GO TO 6.

RECHECK FOR ANY SYMPTOMS

Perform a complete operational check for any symptoms. Refer to

HAC-123, "Operational Check"

Does another symptom exist?

YES

>> Refer to

HAC-122, "How to Perform Trouble Diagnosis For Quick And Accurate Repair"

>> Replace A/C auto amp. Refer to

VTL-8, "Removal and Installation"

WJIA1107E

INTAKE DOOR MOTOR

HAC-43

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

HAC

Intake Door Motor Diagnosis Procedure

INFOID:0000000001366710

SYMPTOM:

• Intake door does not change.
• Intake door motor does not operate normally.

DIAGNOSTIC PROCEDURE FOR INTAKE DOOR MOTOR

CHECK A/C AUTO AMP. FOR POWER AND GROUND

Turn ignition switch ON.

Check voltage between A/C auto amp. harness connector M49
terminal 21 and terminal 22 while placing the HVAC system into
self-diagnostic mode.

Is the inspection result normal?

>> GO TO 4.

>> GO TO 3.

CHECK INTAKE DOOR MOTOR CIRCUITS FOR SHORT TO GROUND

Turn ignition switch OFF.

Disconnect the A/C auto amp. harness connector.

Check continuity between A/C auto amp. harness connector
M49 terminal 21, 22 and ground.

Is the inspection result normal?

>> Replace A/C auto amp. Refer to

VTL-8, "Removal and

Installation"

>> Repair or replace harness as necessary.

CHECK A/C AUTO AMP. FOR GROUND AND POWER

Press the BACK button to back out of self-diagnostic mode.

Check voltage between A/C auto amp. harness connector M49
terminal 21 and terminal 22 while placing the HVAC system into
self-diagnostic mode.

Is the inspection result normal?

>> GO TO 5.

>> Replace A/C auto amp. Refer to

VTL-8, "Removal and Installation"

CHECK INTAKE DOOR MOTOR AND CIRCUITS FOR OPEN

Connector

Terminals

Condition

Voltage

(Approx.)

(+) (-)

A/C auto amp.:

M49

Self-diagnostic

mode

Battery volt-

age

AWIIA0146ZZ

21 - Ground

: Continuity should not exist.

22 - Ground

: Continuity should not exist.

AWIIA0147ZZ

Connector

Terminals

Condition

Voltage

(Approx.)

(+) (-)

A/C auto amp.:

M49

22 21

Self-diagnostic

mode

Battery
voltage

AWIIA0148ZZ

HAC-44

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

INTAKE DOOR MOTOR

Turn ignition switch OFF.

Disconnect the A/C auto amp. harness connector.

Check continuity between A/C auto amp. harness connector
M49 terminal 21 and terminal 22.

Is the inspection result normal?

>> Replace intake door motor. Refer to

VTL-27, "Removal

and Installation"

>> GO TO 6.

CHECK INTAKE DOOR MOTOR CIRCUITS FOR OPEN

Disconnect the intake door motor harness connector.

Check continuity between A/C auto amp. harness connector
M49 (A) terminal 21, 22 and the intake door motor harness con-
nector M58 (B) terminal 1, 6.

Is the inspection result normal?

YES

>> Replace intake door motor. Refer to

VTL-27, "Removal

and Installation"

>> Repair or replace harness as necessary.

Continuity should exist.

AWIIA0149ZZ

21 - 6

: Continuity should exist.

22 - 1

: Continuity should exist.

AWIIA0234ZZ

BLOWER MOTOR CONTROL SYSTEM

HAC-45

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

HAC

BLOWER MOTOR CONTROL SYSTEM

System Description

INFOID:0000000001366714

SYSTEM DESCRIPTION

Component Parts

Blower speed control system components are:

• A/C auto amp.
• A/C and AV switch assembly
• Variable blower control
• Front blower motor relay
• Front blower motor
• In-vehicle sensor
• Ambient sensor
• Optical sensor
• Intake sensor

System Operation

Automatic Mode

In the automatic mode, the blower motor speed is calculated by the A/C auto amp. and variable blower control
based on input from the in-vehicle sensor, optical sensor, intake sensor and ambient sensor, and potentio tem-
perature control (PTC).
When the air flow is increased, the blower motor speed is adjusted gradually to prevent a sudden increase in
air flow.
In addition to manual air flow control and the usual automatic air flow control, starting air flow control, low
water temperature starting control and high passenger compartment temperature starting control are avail-
able.

Starting Blower Speed Control

Start up from cold soak condition (Automatic mode).
In a cold start up condition where the engine coolant temperature is below 50

C (122

F), the blower will not

operate at blower speed 1 for a short period of time (up to 210 seconds). The exact start delay time varies
depending on the ambient and engine coolant temperatures.
In the most extreme case (very low ambient temperature) the blower starting delay will be 210 seconds as
described above. After the coolant temperature reaches 50

C (122

F), or the 210 seconds has elapsed, the

blower speed will increase to the objective blower speed.

Start up from usual operating or hot soak condition (Automatic mode).
The blower will begin operation momentarily after the AUTO switch is pushed. The blower speed will gradually
rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective
blower speed).

AWIIA0173GB

HAC-46

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

BLOWER MOTOR CONTROL SYSTEM

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 speed will vary depending on the sunload. During conditions of low or no sunload, the blower
operates at low speed. During high sunload conditions, the A/C auto amp. causes the blower speed to
increase.

Blower Speed Control Specification

COMPONENT DESCRIPTION

Variable Blower Control

The variable blower control is located on the cooling unit. The vari-
able blower control receives a gate voltage from the A/C auto amp.
to steplessly maintain the blower motor voltage in the 0 to 5 volt
range (approx.).

Front Blower Motor Component Function Check

INFOID:0000000001366715

INSPECTION FLOW

CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - FRONT BLOWER

Press the blower (+) switch. Blower should operate.

Rotate the front blower control dial clockwise, and continue checking blower speed and fan symbol until
all speeds are checked.

Can the symptom be duplicated?

YES

>> GO TO 3.

>> GO TO 2.

CHECK FOR ANY SYMPTOMS

Perform a complete operational check for any symptoms. Refer to