The ground for the relays themselves is actually the PCM. The PCM sends a ground signal to the relays and they energize the loads. The ground for the Fans themselves is the upper left of the engine.
If the PCM is not grounding the relays to activate them, then the PCM may be getting a signal from one of the sensors so that the PCM logic would indicate to de-energize the relays. Some instances of that would be
WOT- Wide open throttle
Overheating -the PCM shuts off the AC if the engine temp or transmission temp is too high.
A/C over pressure sensor--- Your car may or may not have an over pressure sensor located in the high side of the A/C system, or located on backside the compressor itself.
Thursday, July 22nd, 2021 AT 12:21 PM