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 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.ECON switch.
6. Confirm that the set temperature remains at previous temperature.
7. Press OFF switch.

NG: go to trouble diagnosis procedure for memory function "Memory Function"

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.

NG: go to trouble diagnosis procedure for blower motor "Blower Motor Circuit"

OK: continue with next check.







CHECKING DISCHARGE AIR
1. Press MODE switch four times 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".

Intake door position is checked in the next step.

NG: go to trouble diagnosis procedure for intake door motor "Intake Door Motor Circuit"

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 recirculation (REC) switch one time. Recirculation indicator should illuminate.
2. Listen for intake door position change (you should hear blower sound change slightly).

NG: go to trouble diagnosis procedure for intake door "Intake Door Motor Circuit" .

OK: continue with next check.







CHECKING TEMPERATURE DECREASE
1. Press the TEMP (DOWN) switch until 18 °C (60 °F) is displayed.
2. Check for cold air at discharge air outlets.

NG: go to trouble diagnosis procedure for insufficient cooling "Insufficient Cooling" .

OK: continue with next check.







CHECKING TEMPERATURE INCREASE
1. Press the TEMP (UP) switch until 32 °C (90 °F) is displayed.
2. Check for hot air at discharge air outlets.

NG: go to trouble diagnosis procedure for insufficient heating "Insufficient Heating" .

OK: continue with next check.







CHECKING AUTO.ECON MODE
1. Press AUTO.ECON switch.
2. Display should indicate AUTO (not ECON).
3. Press AUTO.ECON switch again.
4. Display should indicate ECON.
Confirm that the compressor clutch engages (sound or visual inspection). (Discharge air and blower speed will depend on ambient, in-vehicle, and set temperatures.)

NG: go to trouble diagnosis procedure for A/C system "Power Supply and Ground Circuit for Auto Amp.", then if necessary, trouble diagnosis procedure for magnet clutch "Magnet Clutch Circuit" .

If all operational checks are OK (symptom cannot 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.
How to Perform Electrical Incident Simulation Tests

If symptom appears, refer to "How to Perform Efficient Diagnosis for Electrical Incident" and perform applicable trouble diagnosis procedures.
How to Perform Electrical Incident Simulation Tests