Control Module HVAC: Testing and Inspection

A/C Amplifier Inspection:

ENGINE SPEED DETECTING CIRCUIT (2S-E ENGINE)

1. Run engine with A/C operating. Check that compressor clutch disengages at:

Cut-Off rpm: 600 - 700 rpm

2. If cut-off rpm is too high, turn amplifier adjust knob clockwise to adjust.
3. If cut-off rpm is too low, turn amplifier adjust knob counter clockwise to adjust.

TEMPERATURE DETECTING CIRCUIT

1. Remove glove box with undercover.
2. Unplug thermistor and connect a variable resistor.
3. Run engine with A/C set for maximum cooling:
a. Air Intake Control: "RECIRC"
b. Air Flow Control: "VENT"
c. Temperature Control: "COOL"
d. Blower Control: "HI"

4. Measure resistance of variable resistor when compressor clutch engages and disengages. If resistance is not between two lines shown on image chart, adjust amplifier:
a. If resistance is too high, turn temperature adjusting screw clockwise.
b. If resistance is too low or evaporator is frosted, turn screw counter clockwise until clutch engages at the specified resistance.