Control Module HVAC: Testing and Inspection

Thermo Control Amplifier Check:

1. Run engine and operate A/C system.
2. Connect the voltmeter from the harness side, leaving the plug connected.
3. Check Thermo Control Amplifier as follows...

Evaporator outlet air temperature decreasing to 2.5-3.5°C (37-38°F)
Thermo Amplifier operation off: Approx. 12 Volts DC

Evaporator outlet air temperature increasing to 4.0-5.0°C (39-41°F)
Thermo Amplifier operation on: Approx. 0 Volts DC