Initial Inspection and Diagnostic Overview

The purpose of the operational check is to confirm that the system operates as it should. The systems which are checked are the blower, mode (discharge air), intake air, temperature decrease, temperature increase, and compressor.

CONDITIONS:
Engine running at normal operating temperature.

PROCEDURE:
1. Check Blower Motor




1. Turn fan control knob to 1-speed. Blower should operate on 1-speed.
2. Then turn fan control knob to 2-speed, and continue checking blower speed until all four speeds are checked.
3. Leave blower on 4-speed.
If NG, go to "TROUBLE DIAGNOSIS PROCEDURE FOR BLOWER MOTOR".
Blower Motor

If OK, continue with the check.

2. Check Discharge Air




1. Turn mode control knob to each mode position.




2. 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".
Mode Door

If OK, continue with next check.




3. Check Recirculation
1. Press recirculation switch.
Recirculation indicator should light.
2. Listen for intake door position to change (you should hear blower sound change slightly).
If NG, go to "TROUBLE DIAGNOSIS PROCEDURE FOR INTAKE DOOR".
Intake Door Motor
If OK, continue with next check.




4. Check Temperature Decrease
1. Turn temperature control knob to full cold.
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.




5. Check Temperature Increase
1. Turn temperature control knob to full hot.
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.




6. Check A/C Switch
1. Turn fan control knob to the desired (1 to 4 speed) position.
2. Push the A/C switch to turn ON the air conditioner.
The indicator lamp should come on when air conditioner is ON.
3. Confirm that the compressor clutch engages (audio or visual inspection).
4. Check for cold air at the appropriate discharge air outlets.
If NG, go to "TROUBLE DIAGNOSIS PROCEDURE FOR MAGNET CLUTCH".
Magnet Clutch

If OK, continue with next check.

If all operational checks are OK (symptom cannot be duplicated), go to "How to Perform Efficient Diagnosis for an Electrical Incident" Diagnostic Aidsand perform tests to simulate driving conditions environment. If symptom appears, refer to "SYMPTOM TABLE"and perform applicable trouble diagnosis procedures. Symptom Related Diagnostic Procedures