System Description

Whenever the ignition switch is in the "ON" position, Battery voltage is applied through the GAUGE Fuse and AUDIO ALARM MODULE to the coil of the Heater Relay. With the BLOWER SWITCH in any position but "OFF," the Heater Relay coil is provided with a ground through the BLOWER SWITCH at JUNCTION BLOCK 4. With a ground provided, the Heater Relay is energized, the relay contacts close, and Battery voltage is applied through the Heater Circuit Breaker, the closed Heater Relay contacts, and the AIC Fuse to the coil of the A/C Clutch Relay.

When the proper inputs and signals are received, the AIC AMPLIFIER provides a ground for the coil of the A/C Clutch Relay. This set of inputs and signals includes the following:

^ Power input indicating that the A/C SWITCH has been turned to "ON."

^ THERMISTOR input indicating that the evaporative temperature of the refrigerant is 10 C (340 F) or above.

^ DUAL PRESSURE SWITCH signal indicating that refrigerant pressure is between 206 kPa (30 psi) and 2648 kPa (384 psi).

Absence of an A/C cutout signal from the ENGINE CONTROL MODULE (ECM). If the A/C AMPLIFIER receives an A/C cutout signal, indicating an increased engine load, air conditioning system operation is terminated until the signal is no longer applied by the ECM.


^ An engine speed input from the DISTRIBUTOR (Base and LSi models) or the IGNITER (GSi models).

^ A closed A/C COMPRESSOR TEMPERATURE SWITCH, indicating that the A/C compressor case temperature is within operating limits (GSi models only).


When the A/C AMPLIFIER provides a ground for the A/C Clutch Relay, the relay is energized, the contacts close and Battery voltage is applied through the ECU-IG Fuse and the closed contacts of the A/C Clutch Relay to the A/C COMPRESSOR CLUTCH.

On GSi models, the A/C COMPRESSOR TEMPERATURE SWITCH must also be closed before the A/C COMPRESSOR CLUTCH receives voltage. With voltage applied, the AIC COMPRESSOR CLUTCH engages and A/C System operation begins. When the A/C Clutch Relay is energized, the ECM is provided with a signal that indicates that the AIC COMPRESSOR CLUTCH is engaged. For more information regarding the A/C signal to the ECM. On GSi models, the A/C AMPLIFIER also receives an "A/C Clutch ON" signal.