Power Supply and Ground Circuit For Auto Amp

TROUBLE DIAGNOSIS


Power Supply and Ground Circuit for Auto Amp.

SYMPTOM: A/C system does not activate.

INSPECTION FLOW











COMPONENT DESCRIPTION

Unified Meter and A/C Amp. (Automatic Amplifier)





- The unified meter and A/C amp. has a built-in microcomputer which processes information sent from various sensors needed for air conditioner operation. The air mix door motor, mode door motor, upper ventilator door motor, intake door motor, blower motor and compressor are then controlled.
- When the various switches and temperature control switch are operated, data is input to the unified meter and A/C amp. from the
AV control unit using CAN communication.
- Self-diagnosis functions are also built into unified meter and A/C amp. to provide quick check of malfunctions in the auto air conditioner system.

Potentio Temperature Control (PTC)





The PTC is built into the multifunction switch. It can be set at an interval of 0.5�C (1.0�F) in the 18�C (60�F) to 32�C (90�F) temperature range by pressing temperature control switch. The set temperature is displayed.

DIAGNOSIS PROCEDURE FOR A/C SYSTEM





SYMPTOM: A/C system does not come on.
1.CHECK POWER SUPPLY CIRCUIT FOR UNIFIED METER AND A/C AMP.
1. Disconnect unified meter and A/C amp. connector.





2. Check voltage between unified meter and A/C amp. harness connector M65 terminals 41, 53 and 54 and ground.










OK or NG
OK - GO TO 2.
NG - Check 10A fuses [Nos. 6, 12 and 19, located in the fuse block (J/B)]. Fuse Block - Junction Box (J/B).
- If fuses are OK, check harness for open circuit. Repair or replace if necessary.
- If fuses are NG, check harness for short circuit and replace fuse.
2.CHECK GROUND CIRCUIT FOR UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.





2. Check continuity between unified meter and A/C amp. harness connector M65 terminal 55, 71 and ground.

55, 71 - Ground: Continuity should exist.

OK or NG
OK - Replace unified meter and A/C amp.
NG - Repair harness or connector.