hey everyone moving this into the thirdgen section...

Hi everyone, well I just got my car back from the autobody repainted etc. Ok so I reinstalled my fans and the whole nine. I had originally removed all that stuff to make the painting of the car easier for the painters.

well my primary fan does not come on when the car gets hot. My Heavy duty cooling fan does kick on at 240 like is suppose to but the primary does not kick on at all. I plugged in the scan tool into the ALDL and turned the key to run and as I found out in the book that energizes all relays (except the fuel pump) and that turned on my primary fan. So the fan motor is working.

Now I know what you are thinking its the coolant temperature sensor at the front of the block. well I changed that sensor about 8 months ago with one from autozone it was a "Wells" brand. Now I am questioning whether that was wise or not. I also changed the heavy duty coolant fan switch at the rear of the passenger block (again with a wells) and finally I yesterday I changed the coolant temperature sender (the one the sends readings to the temp gauge)

Primary fan again is not kicking on. So either my guage is messed up and or the sensor is messed up and or of course one of my wires is bad from what I have gathered at this point.

Does anyone know if there is a way to check the temp that the sensor is registering? I read that a thermometer is an option (maybe I can go buy one at pepboys or something)

Any other suggestions would be greatly appreciated



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Fan Schematics that I scanned:
General Overview of Fans


Chart C-12 - Fan Schematics Overview 1of2


Chart C-12 - Fan Trouble Shooting Chart 1of2


Chart C-12 - Fan Schematics Overview 2of2


Chart C-12 - Fan Trouble Shooting Chart 2of2


Fan Relay 1 Overview


Fan Relay 2 Overview (Heavy Duty Fan Relay)


Ok so there it is dam that took some time but def hope it helps others out there!

 

The scan tool should also read the coolant temp sensor, unless it just a code scanner.
Barring a wiring problem, the ECM is at fault, it's probably sending the signal to turn on the primary fan, but the relay driver isn't pulling the negative side of the relay coil to ground.

 

Well, if you short the ALDL and it comes on, the relay and fan and wiring are good, so it must be the Coolant Temp Sender "yellow and black wires"...or ECM.
Don't use teflon tape or sealer on the threads, it might not ground properly.
Autozone can scan it for free, and use monitor mode to see real time data to see what your sensor sees.