A/C Signal: Description and Operation

PURPOSE
Provides PCM control of the A/C clutch to improve idle quality and engine performance.

CONSTRUCTION
The PCM controlled A/C circuit system consists of:
- Heater and A/C control assembly located at the dashboard.
- Two A/C pressure switches (LOW and HIGH).
- Control relay.
- Compressor clutch.
- Power Steering High Pressure Switch.

OPERATION
The A/C control relay is controlled by the PCM. This allows the PCM to:
- Delay clutch engagement until idle speed is increased.
- Release clutch when idle speed is to low.
- Smooths cycling of the compressor by providing additional fuel at the instant clutch is applied.

Turning "ON" air conditioning supplies battery voltage to the the clutch control relay and terminal "E12". After a time delay of about 1/2 second the PCM will ground terminal "E3" and close the control relay. A/C compressor clutch will then engage.