Air Mix Door Motor Circuit
TROUBLE DIAGNOSIS
Air Mix Door Motor Circuit
SYMPTOM:
- Discharge air temperature does not change.
- Air mix door motor does not operate.
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - TEMPERATURE INCREASE
1. Turn the temperature control dial clockwise to maximum heat.
2. 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.
Can a symptom be duplicated?
YES - GO TO 4.
NO - GO TO 3.
3.PERFORM COMPLETE OPERATIONAL CHECK
Perform a complete operational check and check for any symptoms. Refer to Operational Check (Front).
Can a symptom be duplicated?
YES - Refer to Work Flow.
NO - System OK.
4.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
- GO TO 5.
5.CHECK AIR MIX DOOR OPERATION
Check and verify air mix door mechanism for smooth operation from maximum cold to maximum heat in each mode.
OK or NG
OK - GO TO 6.
NG - Repair as necessary.
6.PERFORM SELF-DIAGNOSIS
Perform self-diagnosis to check for any codes. Refer to A/C System Self-Diagnosis Function.
Are any self-diagnosis codes present?
YES - Refer to A/C System Self-Diagnosis Function.
NO - GO TO 7.
7.CHECK THE AIR MIX DOORS MOTOR PBR CIRCUIT
Perform diagnostic procedure for the air mix door motors. Refer to "Air Mix Door Motor Circuit ".
OK or NG
OK - GO TO 8.
NG - Repair PBR circuit or replace air mix door motor. Refer to Removal And Installation.
8.RECHECK FOR CODES
Perform self-diagnosis. Refer to A/C System Self-Diagnosis Function.
Are any self-diagnostic codes present?
YES - Refer to A/C System Self-Diagnosis Function.
NO - GO TO 9.
9.RECHECK FOR ANY SYMPTOMS
Perform a complete operational check for any symptoms. Refer to Operational Check (Front).
Does another symptom exist?
YES - Refer to Work Flow.
NO - Replace front air control. Refer to Service and Repair.
System Description
Component Parts
Air mix door control system components are:
- Front air control
- Air mix door motors (Front and rear)
- PBR (built-into air mix door motor)
System Operation
The front air control receives data based on the temperature selected by the driver and rear passenger. The front air control then applies a voltage to one circuit of the appropriate air mix door motor, while ground is applied to the other circuit, causing the appropriate 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 measuring the voltage signal on the PBR circuits of each door.
Air Mix Door Control Specification
COMPONENT DESCRIPTION
Air Mix Door Motors
The air mix door motor (front) (1) is attached to the front heater & cooling unit assembly. The rear air mix door motor is attached to the rear heater and cooling unit. These motors rotate so that the air mix door is opened or closed to a position set by the front (or rear) 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 motors.
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (FRONT)
1.CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial to maximum heat.
3. Check voltage between front air control harness connector M49 terminal 18 and terminal 17 while rotating temperature control dial (front) to maximum cold.
OK or NG
OK - GO TO 3.
NG - GO TO 2.
2.CHECK AIR MIX DOOR MOTOR (FRONT) CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 18, 17 and ground.
OK or NG
OK - Replace front air control. Refer to Service and Repair.
NG - Repair or replace harness as necessary.
3.CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (front) to maximum cold.
3. Check voltage between front air control harness connector M49 terminal 18 and terminal 17 while rotating temperature control dial (front) to maximum heat.
OK or NG
OK - GO TO 4.
NG - Replace front air control. Refer to Service and Repair.
4.CHECK AIR MIX DOOR MOTOR (FRONT) CIRCUITS FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 18 and terminal 17.
Continuity should exist.
OK or NG
OK - GO TO 6.
NG - GO TO 5.
5.CHECK AIR MIX DOOR MOTOR (FRONT) CIRCUITS FOR OPEN
1. Disconnect the air mix door motor (front) harness connector.
2. Check continuity between front air control harness connector M49 (A) terminal 18, 17 and the air mix door motor (front) harness connector M307 (B) terminal 5, 6.
OK or NG
OK - Replace air mix door motor (front). Refer to Removal And Installation.
NG - Repair or replace harness as necessary.
6.CHECK FRONT AIR CONTROL FOR PBR POWER AND GROUND
1. Reconnect front air control harness connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M50 (B) terminal 28 and front air control harness connector M49 (A) terminal 3.
OK or NG
OK - GO TO 8.
NG - GO TO 7.
7.CHECK PBR REFERENCE VOLTAGE CIRCUIT FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M50 terminal 28 and ground.
Continuity should not exist.
OK or NG
OK - Replace front air control. Refer to Service and Repair.
NG - Repair or replace harness as necessary.
8.CHECK PBR REFERENCE VOLTAGE AND GROUND CIRCUITS
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M50 (B) terminal 28 and front air control harness connector M49 (A) terminal 3.
Continuity should exist.
OK or NG
OK - GO TO 10.
NG - GO TO 9.
9.CHECK PBR REFERENCE VOLTAGE CIRCUIT FOR OPEN
1. Disconnect the air mix door motor (front) harness connector.
2. Check continuity between air mix door motor (front) harness connector M307 (B) terminal 3 and front air control harness connector M50 (C) terminal 28.
28 - 3 : Continuity should exist.
3. Check continuity between air mix door motor (front) harness connector M39 (B) terminal 1 and front air control harness connector M49 (A) terminal 3.
3 - 1 : Continuity should exist.
OK or NG
OK - Replace air mix door motor (front). Refer to Removal And Installation.
NG - Repair or replace harness as necessary.
10.CHECK PBR FEEDBACK VOLTAGE
1. Reconnect the front air control harness connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M49 terminal 6 and ground while rotating temperature control dial from maximum heat to maximum cold.
Voltage : Approx. 0 - 5V
OK or NG
OK - GO TO 12.
NG - GO TO 11.
11.CHECK PBR FEEDBACK SIGNAL CIRCUIT FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 6 and ground.
Continuity should not exist.
OK or NG
OK - Replace front air control. Refer to Service and Repair.
NG - Repair or replace harness as necessary.
12.CHECK PBR FEEDBACK CIRCUIT FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the air mix door motor (front) harness connector and front air control harness connector.
3. Check continuity between air mix door motor (front) harness connector M307 (B) terminal 2 and front air control harness connector M49 (A) terminal 6.
Continuity should exist.
OK or NG
OK - Replace air mix door motor (rear). Refer to Component Removal And Installation.
NG - Repair or replace harness as necessary.
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (REAR)
1.CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (rear) to maximum heat.
3. Check voltage between front air control harness connector M50 terminal 43 and terminal 44 while rotating temperature control dial (rear) to maximum cold.
OK or NG
OK - GO TO 3.
NG - GO TO 2.
2.CHECK AIR MIX DOOR MOTOR (REAR) CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M50 terminal 43, 44 and ground.
OK or NG
OK - Replace front air control. Refer to Service and Repair.
NG - Repair or replace harness as necessary.
3.CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (rear) to maximum cold.
3. Check voltage between front air control harness connector M50 terminal 43 and terminal 44 while rotating temperature control dial (rear) to maximum hot.
OK or NG
OK - GO TO 4.
NG - Replace front air control. Refer to Service and Repair.
4.CHECK AIR MIX DOOR MOTOR (REAR) CIRCUITS FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M50 terminal 43 and terminal 44.
Continuity should exist.
OK or NG
OK - GO TO 6.
NG - GO TO 5.
5.CHECK AIR MIX DOOR MOTOR (REAR) CIRCUITS FOR OPEN
1. Disconnect the air mix door motor (rear) harness connector.
2. Check continuity between front air control harness connector M50 (A) terminal 43, 44 and the air mix door motor (rear) harness connector B146 (B) terminal 1, 6.
OK or NG
OK - Replace air mix door motor (rear). Refer to Removal And Installation.
NG - Repair or replace harness as necessary.
6.CHECK FRONT AIR CONTROL FOR PBR POWER AND GROUND
1. Reconnect front air control harness connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M50 (B) terminal 28 and front air control harness connector M49 (A) terminal 3.
OK or NG
OK - GO TO 8.
NG - GO TO 7.
7.CHECK PBR REFERENCE VOLTAGE CIRCUIT FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M50 terminal 28 and ground.
Continuity should not exist.
OK or NG
OK - Replace front air control. Refer to Service and Repair.
NG - Repair or replace harness as necessary.
8.CHECK PBR REFERENCE VOLTAGE AND GROUND CIRCUITS
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M50 (B) terminal 28 and front air control harness connector M49 (A) terminal 3.
Continuity should exist.
OK or NG
OK - GO TO 10.
NG - GO TO 9.
9.CHECK PBR REFERENCE VOLTAGE CIRCUIT FOR OPEN
1. Disconnect the air mix door motor (rear) harness connector.
2. Check continuity between air mix door motor (rear) harness connector B146 (B) terminal 3 and front air control harness connector M50 (C) terminal 28.
28 - 3 : Continuity should exist.
3. Check continuity between air mix door motor (rear) harness connector B146 (B) terminal 2 and front air control harness connector M49 (A) terminal 3.
3 - 2 : Continuity should exist.
OK or NG
OK - Replace air mix door motor (rear). Refer to Removal And Installation.
NG - Repair or replace harness as necessary.
10.CHECK PBR FEEDBACK VOLTAGE
1. Reconnect the front air control harness connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M50 terminal 30 and ground while rotating temperature control dial (rear) from maximum cold to maximum hot.
Voltage : Approx. 0 - 5V
OK or NG
OK - GO TO 12.
NG - GO TO 11.
11.CHECK PBR FEEDBACK SIGNAL CIRCUIT FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect front air control harness connector.
3. Check continuity between front air control harness connector M50 terminal 30 and ground.
Continuity should not exist.
OK or NG
OK - Replace front air control. Refer to Service and Repair.
NG - Repair or replace harness as necessary.
12.CHECK PBR FEEDBACK CIRCUIT FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the air mix door motor (rear) harness connector and front air control harness connector.
3. Check continuity between air mix door motor (rear) harness connector B146 (B) terminal 4 and front air control harness connector M50 (A) terminal 30.
Continuity should exist.
OK or NG
OK - Replace air mix door motor (rear). Refer to Component Removal And Installation,
NG - Repair or replace harness as necessary.