Control Module HVAC: Testing and Inspection

Fig. 70 Thermo control testing:

1. Place mode control in A/C position and place blower and ignition in on position.
2. Connect voltmeter between terminals 7 and 9 and between terminals 7 and 13Fig. 70.

NOTE: Leave control connected to wiring harness and insert voltmeter probes into rear of connector, making sure that probes contact terminals.

3. Voltmeter should indicate battery voltage.
4. Disconnect 2 wire connector to thermistor and connect voltmeter between terminals 7 and 12. Meter should read 0 volts.
5. Connect a jumper wire across thermistor terminals 16 and 17 on control. Meter should indicate battery voltage between terminals 7 and 12.
6. Remove jumper wire and voltmeter.
7. Connect a 3.1K ohm resistor between thermistor terminals on control. Control should not click.
8. Connect a 2.55K ohm resistor between thermistor terminals on control. Control should click.