Initial Inspection and Diagnostic Overview

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

Conditions: Engine running and at normal operating temperature






CHECKING MEMORY FUNCTION
1. Set the temperature 90 °F or 32 °C.
2. Press OFF switch.
3. Turn the ignition switch OFF.
4. Turn the 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.
Memory Function

If OK, continue with next check.






CHECKING BLOWER
1. Press fan switch (up side) one time. Blower should operate on low speed. The fan symbol should have one blade lit.
2. Press fan switch (up side) one more time, 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 blower motor.
Blower Motor

If OK, continue with next check.






CHECKING DISCHARGE AIR
1. Press mode switch four times and DEF button.
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.
Intake door position is checked in the next step.

If NG, go to trouble diagnosis procedure for intake door motor.
Intake Door Motor

If OK, continue with next check.


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






CHECKING RECIRCULATION
1. Press intake switch one time. Recirculation indicator should illuminate.
2. Listen for intake door position 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.






CHECKING TEMPERATURE DECREASE
1. Turn the temperature dial 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 the temperature dial 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 ECON (ECONOMY) MODE
1. Set the temperature 75 °F or 25 °C.
2. Press ECON switch.
3. Display should indicate ECON (no AUTO).
Confirm that the compressor clutch is not engaged (visual inspection). (Discharge air and blower speed will depend on ambient, in-vehicle, and set temperatures.)

If NG, go to trouble diagnosis procedure for ECON (Economy) mode.
ECON (Economy) Mode Does Not Operate

If OK, continue with next check.






CHECKING AUTO MODE
1. Press A/C switch.
2. Display should indicate AUTO (no ECON).
Confirm that the compressor clutch engages (audio 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 A/C system, then if necessary, trouble diagnosis procedure for magnet clutch.
Magnet Clutch

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

Symptom Matrix Chart