Initial Inspection and Diagnostic Overview

Operational Check
The purpose of the operational check is to confirm that the system operates properly.

Conditions: Engine running and at usual operating temperature




CHECKING MEMORY FUNCTION
1. Set the temperature to 32 °C (90 °F).
2. Press OFF switch.
3. Turn ignition switch OFF.
4. Turn ignition switch ON.
5. Press the AUTO switch.
6. Confirm that the set temperature remains at previous temperature.
7. Press OFF switch.

If NG, go to trouble diagnosis procedure for "Memory Function".

If OK, continue with next check.




CHECKING BLOWER
1. Turn fan control dial clockwise. Blower should operate on low speed. The fan symbol should have one blade lit.
2. Turn fan control dial clockwise again, and continue checking blower speed and fan symbol until all speeds are checked.
3. Leave blower on MAX speed.

If NG, go to trouble diagnosis procedure for "DIAGNOSTIC PROCEDURE FOR BLOWER MOTOR". Blower Motor Circuit

If OK, continue with next check.

CHECKING DISCHARGE AIR
1. Press MODE switch and DEF switch.




2. Each position indicator should change shape.




3. Confirm that discharge air comes out according to the air distribution table. Refer to "Discharge Air Flow". Discharge Air Flow

If NG, go to trouble diagnosis procedure for "Mode Door Motor Circuit". Mode Door Motor Circuit

If OK, continue with next check.

NOTE: Confirm that the compressor clutch is engaged (sound or visual inspection) and intake door position is at FRESH when the DEF or D/F is selected.




CHECKING RECIRCULATION
1. Press recirculation (REC) switch one time. Recirculation indicator should illuminate.
2. Press fresh (FRE) switch one time. Fresh indicator should illuminate.
3. Listen for intake door position change (you should hear blower sound change slightly).

If NG, go to trouble diagnosis procedure for "Intake Door Motor Circuit". Intake Door Motor Circuit

If OK, continue with next check.

NOTE: Confirm that the compressor clutch is engaged (sound or visual inspection) and intake door position is at FRESH when the DEF or D/F is selected.




CHECKING TEMPERATURE DECREASE
1. Turn temperature dial (driver side) counterclockwise until 18 °C (60 °F) is displayed.
2. Check for cold air at discharge air outlets.

If NG, go to trouble diagnosis procedure for "Insufficient Cooling". Insufficient Cooling (Performance Test)

If OK, continue with next check.




CHECKING TEMPERATURE INCREASE
1. Turn temperature dial (driver side) clockwise until 32 °C (90 °F) is displayed.
2. Check for hot air at discharge air outlets.

If NG, go to trouble diagnosis procedure for "Insufficient Heating". Insufficient Heating

If OK, continue with next check.




CHECK A/C SWITCH
1. Press AUTO switch and A/C switch.
2. A/C switch indicator will turn ON.
- Confirm that the compressor clutch engages (sound or visual inspection).

If NG, go to trouble diagnosis procedure for "Magnet Clutch Circuit". Magnet Clutch Circuit

If OK, continue with next check.




CHECKING AUTO MODE
1. Press AUTO switch and A/C switch.
2. Display should indicate AUTO.
- Confirm that the compressor clutch engages (sound or visual inspection). (Discharge air and blower speed will depend on ambient, in-vehicle, and set temperatures.)

If NG, go to trouble diagnosis procedure for "Power Supply and Ground Circuit for Auto Amp.", Power Supply and Ground Circuit For Auto Amp.then if necessary, trouble diagnosis procedure for "Magnet Clutch Circuit". Magnet Clutch Circuit

If all operational checks are OK (symptom cannot be duplicated), go to malfunction Simulation Tests in "How to Perform Efficient Diagnosis for an Electrical Incident" and perform tests as shown to simulate driving conditions environment. If symptom appears, refer to "SYMPTOM TABLE" and perform applicable trouble diagnosis procedures.