Defroster Door Motor Circuit

DEFROSTER DOOR MOTOR CIRCUIT


Defroster Door Motor Diagnosis Procedure


SYMPTOM:
- Defroster door does not change.
- Defroster door motor does not operate normally.

DIAGNOSTIC PROCEDURE FOR DEFROSTER DOOR MOTOR
1.CHECK A/C AUTO AMP. FOR POWER AND GROUND





1. Turn ignition switch ON.
2. Press the defroster switch ( ).
3. Check voltage between A/C auto amp. harness connector M49 terminal 24 and terminal 23 and press the defroster switch ( ) again.





Is the inspection result normal?
YES - GO TO 3.
NO - GO TO 2.
2.CHECK DEFROSTER DOOR MOTOR CIRCUITS FOR SHORT TO GROUND





1. Turn ignition switch OFF.
2. Disconnect the A/C auto amp. harness connector.
3. Check continuity between A/C auto amp. harness connector
M49 terminal 23, 24 and ground.

23 - Ground : Continuity should not exist.
24 - Ground : Continuity should not exist.

Is the inspection result normal?
YES - Replace A/C auto amp. Refer to Service and Repair.
NO - Repair or replace harness as necessary.
3.CHECK A/C AUTO AMP. FOR GROUND AND POWER





1. Press the defroster switch ( ).
2. Check voltage between A/C auto amp. harness connector M49 terminal 23 and terminal 24 and press the defroster switch ( ) again.





Is the inspection result normal?
YES - GO TO 4.
NO - Replace A/C auto amp. Refer to Service and Repair.
4.CHECK DEFROSTER DOOR MOTOR AND CIRCUITS FOR OPEN





1. Turn ignition switch OFF.
2. Disconnect the A/C auto amp. harness connector.
3. Check continuity between A/C auto amp. harness connector
M49 terminal 23 and terminal 24.

Continuity should exist.

Is the inspection result normal?
YES - GO TO 6.
NO - GO TO 5.
5.CHECK DEFROSTER DOOR MOTOR CIRCUITS FOR OPEN





1. Disconnect the defroster door motor harness connector.
2. Check continuity between A/C auto amp. harness connector
M49 (A) terminal 23, 24 and the defroster door motor harness connector M144 (B) terminal 1, 6.

23 - 1 : Continuity should exist.
24 - 6 : Continuity should exist.

Is the inspection result normal?
YES - Replace defroster door motor. Refer to Defroster Door Motor.
NO - Repair or replace harness as necessary.
6.CHECK A/C AUTO AMP. FOR PBR POWER AND GROUND





1. Reconnect A/C auto amp. harness connector.
2. Turn ignition switch ON.
3. Check voltage between A/C auto amp. harness connector M50
(A) terminal 28 and M49 (B) terminal 3.





Is the inspection result normal?
YES - GO TO 8.
NO - GO TO 7.
7.CHECK PBR REFERENCE VOLTAGE CIRCUIT FOR SHORT TO GROUND





1. Turn ignition switch OFF.
2. Disconnect the A/C auto amp. harness connector.
3. Check continuity between A/C auto amp. harness connector
M50 terminal 28 and ground.

Continuity should not exist.

Is the inspection result normal?
YES - Replace A/C auto amp. Refer to Service and Repair.
NO - Repair or replace harness as necessary.
8.CHECK PBR REFERENCE VOLTAGE AND GROUND CIRCUITS





1. Turn ignition switch OFF.
2. Disconnect the A/C auto amp. harness connector.
3. Check continuity between A/C auto amp. harness connector
M50 (A) terminal 28 and M49 (B) terminal 3.

Continuity should exist.

Is the inspection result normal?
YES - GO TO 10.
NO - GO TO 9.
9.CHECK PBR REFERENCE VOLTAGE CIRCUIT FOR OPEN





1. Disconnect the defroster door motor harness connector.
2. Check continuity between defroster door motor harness connector M144 (B) terminal 3, 2 and A/C auto amp. harness connector
M50 (A) terminal 28, and M49 (C) terminal 3.

28 - 3 : Continuity should exist.
3 - 2 : Continuity should exist.

Is the inspection result normal?
YES - Replace defroster door motor. Refer to Defroster Door Motor.
NO - Repair or replace harness as necessary.
10.CHECK PBR FEEDBACK VOLTAGE





1. Reconnect the A/C auto amp. harness connector.
2. Turn ignition switch ON.
3. Check voltage between A/C auto amp. harness connector M49 terminal 10 and ground while cycling defroster switch on and off.

Voltage : Approx. 1V - 4.5V

Is the inspection result normal?
YES - GO TO 12.
NO - GO TO 11.
11.CHECK PBR FEEDBACK SIGNAL CIRCUIT FOR SHORT TO GROUND





1. Turn ignition switch OFF.
2. Disconnect A/C auto amp. harness connector.
3. Check continuity between A/C auto amp. harness connector
M49 terminal 10 and ground.

Continuity should not exist.

Is the inspection result normal?
YES - Replace A/C auto amp. Refer to Service and Repair.
NO - Repair or replace harness as necessary.
12.CHECK PBR FEEDBACK CIRCUIT FOR OPEN





1. Turn ignition switch OFF.
2. Disconnect the defroster door motor harness connector and A/C auto amp. harness connector.
3. Check continuity between defroster door motor harness connector M144 (B) terminal 4 and A/C auto amp. harness connector
M49 (A) terminal 10

Continuity should exist.

Is the inspection result normal?
YES - Replace defroster door motor. Refer to Defroster Door Motor,
"Removal and Installation".
NO - Repair or replace harness as necessary.