Nissan Titan A60. Manual - part 631

DEFROSTER DOOR MOTOR CIRCUIT

HAC-207

< DTC/CIRCUIT DIAGNOSIS >

[MANUAL A/C (TYPE 2)]

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DEFROSTER DOOR MOTOR CIRCUIT

System Description

INFOID:0000000006164822

SYSTEM DESCRIPTION

Component Parts

Defroster door control system components are:

• Front air control

• Defroster door motor

• PBR (Built into defroster door motor)

• Intake sensor

System Operation

The front air control determines defroster door position based on the position of the defroster switch. When the

defroster switch is depressed, the defroster door motor rotates directing air to the defroster ducts. When any

mode other than defroster is selected, the defroster motor rotates in the opposite direction closing off air flow

to the defroster ducts.

COMPONENT DESCRIPTION

Defroster door motor 

The defroster door motor is attached to the front heater & cooling

unit assembly. The front air control sends a voltage to rotate to the

defroster door directing the air flow either to the defroster ducts, or to

the floor ducts, depending on which way the voltage and ground are

applied to the motor leads. Motor rotation is conveyed to a lever

which activates the defroster door.

Defroster Door Motor Component Function Check

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INSPECTION FLOW

1.

CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - DEFROSTER DOOR

1. Select vent (

) mode.

2. Rotate mode control dial to defrost mode (

). 

3. Listen for defroster door position change (blower sound should change slightly).
Is the inspection result normal?

YES

>> Inspection End.

NO

>> Go to diagnosis procedure. Refer to 

HAC-207, "Defroster Door Motor Diagnosis Procedure"

.

Defroster Door Motor Diagnosis Procedure

INFOID:0000000006164824

Regarding Wiring Diagram information, refer to 

HAC-232, "Wiring Diagram - Manual With 3 Control Dial Sys-

tem"

.

SYMPTOM:

• Defroster door does not change.

• Defroster door motor does not operate normally.

1.

CHECK DEFROSTER DOOR MOTOR CIRCUITS FOR OPEN AND SHORT TO GROUND 

WJIA0592E

HAC-208

< DTC/CIRCUIT DIAGNOSIS >

[MANUAL A/C (TYPE 2)]

DEFROSTER DOOR MOTOR CIRCUIT

1. Turn ignition switch OFF.

2. Disconnect the front air control harness connector M176 (A) and

the defroster door motor harness connector M144 (B).

3. Check continuity between front air control harness connector

M176 (A) terminals 19, 20 and the defroster door motor harness

connector M144 (B) terminals 1, 6.

4. Check continuity between front air control harness connector

M176 terminals 19, 20 and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace harness as necessary.

2.

CHECK FRONT AIR CONTROL FOR DEFROSTER DOOR MOTOR POWER AND GROUND 

1. Reconnect front air control harness connector.

2. Turn ignition switch ON.
3. Press the mode switch to the VENT (

) mode. 

4. Check voltage between front air control harness connector

M176 terminal 19 and terminal 20 while pressing the defroster
switch (

). 

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Replace front air control. Refer to 

VTL-8, "Removal and Installation"

.

3.

CHECK DEFROSTER DOOR MOTOR PBR CIRCUITS FOR OPEN AND SHORT TO GROUND 

1. Turn ignition switch OFF.

2. Disconnect the front air control harness connector M176 (A).

3. Check continuity between front air control harness connector

M176 (A) terminals 15, 2 and the defroster door motor harness

connector M144 (B) terminals 2, 3.

4. Check continuity between front air control harness connector

M176 terminal 2, 15 and ground.

A

B

Continuity

Connector

Terminal

Connector

Terminal

M176

19

M144

1

Yes

20

6

Connector

Terminal

—

Continuity

M176

19

Ground

No

20

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Connector

Terminals

Condition Voltage 

(Approx.)

(+) (-)

M176

19

20

Following defroster switch (

) on

Battery voltage

20

19

Following defroster switch (

) off

Battery voltage

AWIIA0523ZZ

A

B

Continuity

Connector

Terminal

Connector

Terminal

M176

2

M144

3

Yes

15

2

AWIIA0955ZZ

DEFROSTER DOOR MOTOR CIRCUIT

HAC-209

< DTC/CIRCUIT DIAGNOSIS >

[MANUAL A/C (TYPE 2)]

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Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair or replace harness as necessary.

4.

CHECK PBR FEEDBACK SIGNAL CIRCUIT FOR OPEN AND SHORT TO GROUND 

1. Check continuity between front air control harness connector

M176 (A) terminal 25 and defroster door motor harness connec-

tor M144 (B) terminal 4.

2. Check continuity between front air control harness connector

M176 terminal 25 and ground.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Repair or replace harness as necessary.

5.

CHECK FRONT AIR CONTROL FOR 5 VOLT REFERENCE (VREF), VREF RETURN, AND FEEDBACK

SIGNAL 

1. Reconnect front air control harness connectors.

2. Turn ignition switch ON.

3. Check voltage between front air control harness connector

M176 terminals 2, 15.

Connector

Terminal

—

Continuity

M176

2

Ground

No

15

A

B

Continuity

Connector

Terminal

Connector

Terminal

M176

25

M144

4

Yes

AWIIA0534ZZ

Connector

Terminal

—

Continuity

M176

25

Ground

No

AWIIA0533ZZ

Connector

Terminals

Connector

Terminals

Voltage (Approx.)

(+)

(-) 

M176

2

M176

15

5 Volts

AWIIA0494ZZ

HAC-210

< DTC/CIRCUIT DIAGNOSIS >

[MANUAL A/C (TYPE 2)]

DEFROSTER DOOR MOTOR CIRCUIT

4. Check voltage between front air control harness connector

M176 terminal 25 and ground.

Is the inspection result normal?

YES

>> GO TO 7.

NO

>> Replace front air control. Refer to 

VTL-8, "Removal and

Installation"

.

6.

CHECK FRONT AIR CONTROL FOR FEEDBACK SIGNAL 

1. Reconnect the defroster door motor harness connector M144.

2. Check voltage between front air control harness connector

M176 terminal 25 and ground.

Is the inspection result normal?

YES

>> Inspect defroster door for binding or mechanical failure.

If defroster door moves freely, replace front air control.

Refer to 

VTL-8, "Removal and Installation"

.

NO

>> Replace the defroster door motor. Refer to 

VTL-17,

"Removal and Installation"

.

Connector

Terminal

—

Voltage (Approx.)

M176

25

Ground

0 Volts

AWIIA0532ZZ

Connector

Terminal

—

Voltage (Approx.)

M176

25

Ground

0.2 to 4.8 Volts

AWIIA0532ZZ