Nissan Frontier. Manual - part 905

HAC-174

< DTC/CIRCUIT DIAGNOSIS >

[MANUAL A/C (TYPE 2)]

MODE DOOR MOTOR

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Replace front air control. Refer to 

VTL-7, "Removal and Installation"

.

3.

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

1. Turn ignition switch OFF.

2. Disconnect the front air control harness connector M49 (A).

3. Check continuity between front air control harness connector M49 (A) terminals 23, 26 and the mode door

motor harness connector M142 (B) terminals 1, 3.

4. Check continuity between front air control harness connector M49 (A) terminals 23, 26 and ground.

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

M49 terminal 21 and mode door motor harness connector M142

terminal 4.

2. Check continuity between front air control harness connector

M49 terminal 16 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 M49 terminal 23 and terminal 26.

Connector

Terminals

Condition Voltage 

(Approx.)

(+) (-)

M49

1

14

Rotating the mode control dial from 

D/F (

) mode to VENT (

) mode

Battery voltage

14

1

Rotating the mode control dial from 

VENT (

) mode to B/L (

) mode

Battery voltage

A

B

Continuity

Connector

Terminal

Connector

Terminal

M49

23

M142

3

Yes

26

2

Connector

Terminal

—

Continuity

M49 (A)

23

Ground

No

26

Connector

Terminal

Connector

Terminal

Continuity

M49

21

M142

4

Yes

Connector

Terminal

—

Continuity

M49

21

Ground

No

WJIA1089E

MODE DOOR MOTOR

HAC-175

< DTC/CIRCUIT DIAGNOSIS >

[MANUAL A/C (TYPE 2)]

C

D

E

F

G

H

J

K

L

M

A

B

HAC

N

O

P

4. Check voltage between front air control harness connector M49

terminal 21 and ground.

Is the inspection result normal?

YES

>> GO TO 7.

NO

>> Replace front air control. Refer to 

VTL-7, "Removal and

Installation"

.

6.

CHECK FRONT AIR CONTROL FOR FEEDBACK SIGNAL 

1. Reconnect the mode door motor harness connector M142.

2. Check voltage between front air control harness connector M49

terminal 21 and ground.

Is the inspection result normal?

YES

>> Inspect mode door for binding or mechanical failure. If

mode door moves freely, replace front air control. Refer

to 

VTL-7, "Removal and Installation"

.

NO

>> Replace the mode door motor. Refer to 

VTL-21,

"Removal and Installation"

.

Connector

Terminals

Connector

Terminals

Voltage (Approx.)

(+)

(-) 

M49

23

M49

26

5 Volts

Connector

Terminal

—

Voltage (Approx.)

M49

21

Ground

0 Volts

WJIA1088E

Connector

Terminal

—

Voltage (Approx.)

M49

21

Ground

0.2 to 4.8 Volts

WJIA1088E

HAC-176

< DTC/CIRCUIT DIAGNOSIS >

[MANUAL A/C (TYPE 2)]

AIR MIX DOOR MOTOR

AIR MIX DOOR MOTOR

System Description

INFOID:0000000009478388

SYSTEM DESCRIPTION

Component Parts

Air mix door control system components are:

• Front air control

• Air mix door motor 

• Position Balanced Resistor (PBR) (built into air mix door motor)

• Intake sensor

System Operation

The front air control receives data from the temperature selected by the driver. The front air control then

applies a voltage to one circuit of the air mix door motor, while ground is applied to the other circuit, causing

the air mix door motor to rotate. The direction of rotation is determined by which circuit has voltage applied to

it, and which one has ground applied to it. The front air control monitors the air mix door positions by measur-

ing the voltage signal on the PBR circuits of each door.

Air Mix Door Control Specification

COMPONENT DESCRIPTION

Air Mix Door Motor

WJIA1316E

WJIA0435E

AIR MIX DOOR MOTOR

HAC-177

< DTC/CIRCUIT DIAGNOSIS >

[MANUAL A/C (TYPE 2)]

C

D

E

F

G

H

J

K

L

M

A

B

HAC

N

O

P

The air mix door motor is attached to the heater and cooling unit

assembly. This motor rotates so that the air mix door is opened or

closed to a position set by the front air control. Motor rotation is then

conveyed through a shaft and the air mix door position is then fed

back to the front air control by the PBR built into the air mix door

motor.

Air Mix Door Motor Component Function Check

INFOID:0000000009478389

INSPECTION FLOW

1.

CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - TEMPERATURE INCREASE

1. Blower must be on (1, 2, 3, 4).

2. Turn the temperature control dial clockwise to maximum heat.

3. Check for hot air at discharge air outlets.

>> GO TO 2.

2.

CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - TEMPERATURE DECREASE

1. Turn the temperature control dial counterclockwise to maximum cold.

2. Check for cold air at discharge air outlets.
Is the inspection result normal?

YES

>> Inspection End.

NO

>> Go to diagnosis procedure. Refer to 

HAC-177, "Air Mix Door Motor Diagnosis Procedure"

.

Air Mix Door Motor Diagnosis Procedure

INFOID:0000000009478390

Regarding Wiring Diagram information, refer to 

HAC-200, "Wiring Diagram - With Type 2"

.

SYMPTOM:

• Discharge air temperature does not change.

• Air mix door motor does not operate normally.

1.

CHECK AIR MIX DOOR MOTOR CIRCUITS FOR OPEN AND SHORT TO GROUND 

1. Turn ignition switch OFF.

2. Disconnect the front air control harness connector M49 and the air mix door motor harness connector

M147.

3. Check continuity between front air control harness connector M49 terminals 3, 2 and the air mix door

motor harness connector M147 terminals 5, 6.

4. Check continuity between front air control harness connector M49 terminals 3, 2 and ground.

WJIA1636E

Connector

Terminal

Connector

Terminal

Continuity

M49

2

M147

6

Yes

3

5