Operation CHARM: Car repair manuals for everyone.

Control Module HVAC: Testing and Inspection


NOTE: Before this test is performed, check resistance of temperature control resistor and thermistor.

1. Remove glove box and under tray.


Fig. 11 Variable Resistor Connection.:





2. Disconnect thermistor and connect variable resistor, Fig. 11.
3. Place A/C in MAXIMUM, temperature control in COOL, air flow control to VENT and blower control to HI.


Fig. 12 Temperature Detecting Circuit Chart.:





4. Record resistance of variable resistor when compressor clutch engages and disengages. Use chart in Fig. 12 to determine if resistance is out of specification.


Fig. 10 Idle Stabilizer Amplifier Adjusting Screw Location.:





5. Adjust resistance by turning temperature setting resistor clockwise if resistance is too high and counterclockwise is resistance is too low, Fig. 10.