Grand Cherokee 2WD L6-242 4.0L VIN S MFI (1993)
Compressor Clutch Relay: Description and Operation
PURPOSE
By switching the ground path for the relay on and off, the PCM is able to Cycle the A/C clutch based on changes in engine operating conditions.
OPERATION
The Powertrain Control Module (PCM) energizes the A/C relay when the driver selects A/C or defrost switch inside the vehicle. The relay
receives battery voltage from the ignition switch.
When A/C or defrost is selected the PCM receives an A/C request signal. The PCM then energizes the relay, allowing the A/C clutch to engage.
If PCM senses wide open throttle condition, or low idle speed condition, it will de-energize the relay. This prevents A/C clutch engagement.
The PCM will also de-energize the relay if engine coolant temperature excedes 257 °F.
