Control Module HVAC: Adjustments

Idle stabilizer resistance specifications.:

1. Operate engine and air conditioner, then connect a tachometer to the engine.
2. Check cut-in and cut-off engine RPM.
3. If cut-off RPM is not 600-700 RPM, adjust as follows:
a. If cut-off RPM is too high, turn adjusting knob on amplifier clockwise.
b. If cut-off RPM is too low, turn adjusting knob on amplifier counter-clockwise.
c. Recheck cut-off RPM after each adjustment.
4. Disconnect thermistor connector from amplifier and connect suitable variable resistor to amplifier.
5. Operate A/C with controls set for maximum cooling, blower set on high, mode selector in vent position and air intake control set in recirculation position.
6. Observe resistor setting when magnetic clutch engages and disengages.
7. If resistance is not within range shown in graphs, adjust temperature screw on amplifier circuit board as follows:
a. If resistance is too high, turn screw clockwise.
b. If resistance is too low, or if evaporator frosting is experienced, turn screw counterclockwise until clutch engages at proper resistance.
8. Recheck system operation after performing adjustments.