Just trying to figure out what is wrong with my fan, 92 RS V6. Fan never turns on, however if I use the diagnostic mode (to get error codes) the fan will work. Does this mean the relay works? Or is it possible for it to bypass the relay. I can't get ahold of a manual right now. From what i've gleaned from the boards my car uses a coolant temp sensor and the ecm activates the relay to turn on the fan? I'd rather not replace what isn't broke so I'm assuming since the fan will work the sensor is shot and not the relay.

 

Not a tech ...

If your fan works by hot wire testing (battery to fan harness connector) then it sounds like it's a sensor and or the relay.

There is also an online manual by Chilton.

Chilton online Auto Library

 

If the fan works through the stock harness then the relay is fine. Not exactly sure why it runs in diagnostic mode. I'm not too famiiliar with the way the fan works on that motor. Someone else can jump in here, but the relay IS good.