Control Module HVAC: Testing and Inspection

Inspection of HVAC Control Module and Its Circuits

NOTE:

If you connect a voltmeter or ohmmeter directly to the HVAC control module by disconnecting the HVAC control module connector, you can damage the HVAC control module.

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

HVAC control module and its circuits can be checked at HVAC control module wiring connector by measuring voltage and pulse signal.

Voltage Check

1) Remove HVAC control module. Refer to HVAC Control Module Removal and Installation HVAC Control Module Removal and Installation.
2) Connect HVAC control module connector to HVAC control module.
3) Check voltage and/or pulse signal at each terminal of connector connected by referring to HVAC Control Module Voltage Table.











NOTE:

- As each terminal voltage is affected by battery voltage, confirm that it is 11 V or more when ignition switch is ON.
- Voltage with asterisk (*) cannot be measured by voltmeter because it is pulse signal. Check it with oscilloscope if necessary.

HVAC Control Module Voltage Table















Reference waveform No. 1

High and low of CAN communication signals.