Power Supply And Ground Circuit For Front Air Control

TROUBLE DIAGNOSIS


Power Supply and Ground Circuit for Front Air Control


SYMPTOM:
- Heater and A/C system (if equipped) does not come on.

INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK
1. Turn blower control dial to any speed.





2. Turn mode dial to vent ( ) position, and press A/C switch (if equipped).
3. Confirm that the compressor clutch engages (sound or visual inspection).
Can a symptom be duplicated?
YES - GO TO 3.
NO - GO TO 2.
2.PERFORM COMPLETE OPERATIONAL CHECK
Perform a complete operational check and check for any symptoms. Operational Check.
Can a symptom be duplicated?
YES - How To Perform Trouble Diagnosis For Quick And Accurate Repair.
NO - System OK.
3.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
- GO TO 4.
4.CHECK POWER AND GROUND CIRCUIT
Check main power supply and ground circuit. Refer to "DIAGNOSTIC PROCEDURE".
OK or NG
OK - System OK.
NG - Replace front air control. Service and Repair.

COMPONENT DESCRIPTION

FRONT AIR CONTROL





The front air control has a built-in microcomputer which processes information sent from the temperature control dial, and various switches needed for air conditioner operation. The air mix door motor, mode door motor, intake door motor, blower motor and compressor are then controlled.

POTENTIO TEMPERATURE CONTROL (PTC)
The PTC is built into the front air control.

DIAGNOSTIC PROCEDURE

SYMPTOM:





- Heater and A/C system (if equipped) does not come on.
1.CHECK POWER SUPPLY CIRCUIT FOR FRONT AIR CONTROL
1. Disconnect front air control connector M33.
2. Turn ignition switch ON.





3. Check voltage between front air control connector M33 terminals 1, 2, and 21, and ground.





OK or NG
OK - GO TO 2.
NG - Check the following.
- 10A fuse [Nos. 12 and 19, located in the fuse block (J/B)] and 15A fuses [Nos. 10 and 11, located in the fuse block (J/B)].
- If fuses are OK, check for open circuit in wiring harness. Repair or replace as necessary.
- If fuses are NG, replace fuse and check wiring harness for short circuit. Repair or replace as necessary.
2.CHECK BODY GROUND CIRCUIT FOR FRONT AIR CONTROL
1. Turn ignition switch OFF.





2. Check continuity between front air control connector M33 terminal 3 and ground.





OK or NG
OK - Replace front air control. Service and Repair.
- Inspection End.
NG - Repair or replace harness.