Nissan Titan A60. Manual - part 611

DEFROSTER DOOR MOTOR CIRCUIT

HAC-127

< DTC/CIRCUIT DIAGNOSIS >

[MANUAL A/C (TYPE 1)]

C

D

E

F

G

H

J

K

L

M

A

B

HAC

N

O

P

DEFROSTER DOOR MOTOR CIRCUIT

System Description

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SYSTEM DESCRIPTION

Component Parts

Defroster door control system components are:

• Front air control

• Defroster door motor

• Position balanced resistor (PBR) (Built into defroster door motor)

• Ambient sensor

• 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. Press the defrost switch (

). Defroster indicator should illuminate. 

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-127, "Defroster Door Motor Diagnosis Procedure"

Defroster Door Motor Diagnosis Procedure

INFOID:0000000006164765

Regarding Wiring Diagram information, refer to 

HAC-155, "Wiring Diagram - Manual With 2 Control Dial Sys-

tem"

.

SYMPTOM:

• Defroster door does not change.

• Defroster door motor does not operate normally.

WJIA0592E

HAC-128

< DTC/CIRCUIT DIAGNOSIS >

[MANUAL A/C (TYPE 1)]

DEFROSTER DOOR MOTOR CIRCUIT

1.

CHECK DEFROSTER DOOR MOTOR POSITION BALANCED RESISTOR (PBR) FEEDBACK VOLTAGE

1. Turn ignition switch ON.

2. Using CONSULT-III, check "DEF FDBCK" in "DATA MONITOR" mode in "HVAC". Refer to 

HAC-111,

"CONSULT-III Function (HVAC)"

.

3. Observe "DEF FDBCK" voltage while cycling front air control mode switch through all modes and pressing

DEF switch.

Is the inspection result normal?

YES

>> • Defroster door motor is OK.

• Inspect defroster door for mechanical failure. Refer to 

VTL-17, "Removal and Installation"

.

NO

>> GO TO 2.

2.

CHECK DEFROSTER DOOR MOTOR CIRCUITS FOR OPEN AND SHORT TO GROUND 

1. Turn ignition switch OFF.

2. Disconnect the front air control harness connector M180 (A) and

the defroster door motor harness connector M144 (B).

3. Check continuity between front air control harness connector

M180 (A) terminals 23, 24 and the defroster door motor harness

connector M144 (B) terminals 1, 6.

4. Check continuity between front air control harness connector

M180 terminals 23, 24 and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace harness as necessary.

3.

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

M180 terminal 23 and terminal 24 while pressing the defroster
switch (

). 

Is the inspection result normal?

YES

>> GO TO 4.

Monitor Item

Condition

Results

DEF FDBCK

Cycle mode switch through all modes, D/F 

(

), VENT (

), B/L (

), FOOT(

), and 

press DEF (

)

Voltage varies between 0.2 and 4.8 volts.

A

B

Continuity

Connector

Terminal

Connector

Terminal

M180

23

M144

1

Yes

24

6

Connector

Terminal

—

Continuity

M180

23

Ground

No

24

AWIIA0406ZZ

AWIIA0403ZZ

Connector

Terminals

Condition Voltage 

(Approx.)

(+) (-)

M180

23

24

Following defroster switch (

) on

Battery voltage

24

23

Following defroster switch (

) off

Battery voltage

AWIIA0404ZZ

DEFROSTER DOOR MOTOR CIRCUIT

HAC-129

< DTC/CIRCUIT DIAGNOSIS >

[MANUAL A/C (TYPE 1)]

C

D

E

F

G

H

J

K

L

M

A

B

HAC

N

O

P

NO

>> Replace front air control. Refer to 

VTL-8, "Removal and Installation"

.

4.

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

1. Turn ignition switch OFF.

2. Disconnect the front air control harness connectors M180 (C)

and M181 (A).

3. Check continuity between front air control harness connector

M180 (C) terminal 3, and M181 (A) terminal 28 and the defroster

door motor harness connector M144 (B) terminals 2, 3.

4. Check continuity between front air control harness connector M180 (C) terminal 3, M181 (A) terminal 28

and ground.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair or replace harness as necessary.

5.

CHECK PBR FEEDBACK SIGNAL CIRCUIT FOR OPEN AND SHORT TO GROUND 

1. Check continuity between front air control harness connector

M180 (A) terminal 10 and defroster door motor harness connec-

tor M144 (B) terminal 4.

2. Check continuity between front air control harness connector

M180 terminal 10 and ground.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Repair or replace harness as necessary.

6.

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

SIGNAL 

A and C

B

Continuity

Connector

Terminal

Connector

Terminal

M180 (C)

3

M144

2

Yes

M181 (A)

28

3

Connector

Terminal

—

Continuity

M180 (C)

3

Ground

No

M181 (A)

28

AWIIA0393ZZ

A

B

Continuity

Connector

Terminal

Connector

Terminal

M180

10

M144

4

Yes

AWIIA0410ZZ

Connector

Terminal

—

Continuity

M180

10

Ground

No

AWIIA0409ZZ

HAC-130

< DTC/CIRCUIT DIAGNOSIS >

[MANUAL A/C (TYPE 1)]

DEFROSTER DOOR MOTOR CIRCUIT

1. Reconnect front air control harness connectors.

2. Turn ignition switch ON.

3. Check voltage between front air control harness connector

M180   (B) terminal 3, and M181 (A) terminal 28.

4. Check voltage between front air control harness connector

M180 terminal 10 and ground.

Is the inspection result normal?

YES

>> GO TO 7.

NO

>> Replace front air control. Refer to 

VTL-8, "Removal and

Installation"

.

7.

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

M180 terminal 10 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"

.

A

B

Connector

Terminals

Connector

Terminals

Voltage (Approx.)

(+)

(-) 

M181

28

M180

3

5 Volts

AWIIA0407ZZ

Connector

Terminal

—

Voltage (Approx.)

M180

10

Ground

0 Volts

AWIIA0408ZZ

Connector

Terminal

—

Voltage (Approx.)

M180

10

Ground

0.2 to 4.8 Volts

AWIIA0408ZZ