LS swap- Electric fans stay on

75Maro

Veteran Member
Mar 31, 2008
729
Dallas,Tx
trying to diagnose the elec fan ground signal from my PCM. We have the temps set to enable @200 and off @190. As soon as I start the car the PCM grounds the fan wire to the relay. Looking for some help on other inputs the PCM could see that would tell it to turn the fans on. I can monitor the ECT and it’s in line with my analog temp sensor.

Thanks for the help
 

rchydzik

Veteran Member
Lifetime Gold Member
Nov 13, 1999
924
Colbert, WA USA
The pcm has two leads to ac. Most are confgured to run the fans anytime the ac is on. Could one of the ac leads be miswired?
 

badazz81z28

Veteran Member
May 4, 2001
22,131
Alabama
Sounds like an ECM issue or a wiring issue from the ECT sensor if a ground signal is coming from the PCM when it’s not supposed to.
 




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