Control Module HVAC: Testing and Inspection

Inspection of HVAC Control Module and Its Circuit

HVAC control module and its circuits can be checked by measuring terminal voltages of HVAC control module connector.

NOTE:

If you connect a voltmeter or ohmmeter directly to the HVAC control module terminals by removing the HVAC control module connectors, you can damage the HVAC control module.

Never connect a voltmeter or an ohmmeter directly to any terminal of the HVAC control module by disconnecting the HVAC control module connectors.

Voltage Check

1) Remove HVAC control module referring to Service and Repair HVAC Control Module Removal and Installation:Auto A/C.
2) Check voltage at each terminal.

NOTE:

As each terminal voltage is affected by the battery voltage, confirm that the battery voltage is 11 V or more when ignition switch is ON.
























Reference waveform No. 1

Rear defogger switch or A/C switch signal (1)











Reference waveform No. 2

Serial communication line of BCM (1)