Fan control module troubleshooting question

[colonwq]

My '02 GLX is getting hot.
I recently replaced the timing belt (belt, pump, thermostat and coolant). The fans come on when the AC is on high.
I am going through the troubleshooting of the coolant problems (Overheating problem).

The document says to jumper the red and the red/white to start the fans followed by the red to red/yellow wires.
The fan control module (FCM) has two plugs. One has four wires and the other has 14. Which harness should be unplugged? The four wire harness has red, red/white and two fat red/black. The 14 wire has many including the red, red/white and red/black.

Also, removing the FCM is very easy from under the car. Blind removing the two 10MM bolts is much less time consuming than removing the battery and bracket.

Thanks for any information

Keith

[MyOtherRidesAVette]

Originally Posted by colonwq

My '02 GLX is getting hot.
I recently replaced the timing belt (belt, pump, thermostat and coolant). The fans come on when the AC is on high.
I am going through the troubleshooting of the coolant problems (Overheating problem).

The document says to jumper the red and the red/white to start the fans followed by the red to red/yellow wires.
The fan control module (FCM) has two plugs. One has four wires and the other has 14. Which harness should be unplugged? The four wire harness has red, red/white and two fat red/black. The 14 wire has many including the red, red/white and red/black.

Also, removing the FCM is very easy from under the car. Blind removing the two 10MM bolts is much less time consuming than removing the battery and bracket.

Thanks for any information

Keith

I put up the checks below which I captured out of my .pdf you are using from the other thread. Also pics to help you locate components, and the aplicable wiring diagram. The connector is a three wire, red, red/yellow tracer, red/white tracer (ground). You need to re-read, I think your unplugging the harness (not harnesses) from the wrong component. You want the harness plug on the radiator fan thermal switch, not the fan control module.

I hope this additional information helps. I'm going to start linking this thread to other posts. Please keep us all informed and let me know if you need something else, I'm going to start linking this thread to other posts. What is it exactly that you are trying to diagnose? You don't say.

MORAV

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[colonwq]

Thanks for the updated images. My copy was black on black with random-ish specks of white.

I was able to unplug the wire. In order to get my hand in there, I unplugged the rear wire harnesses that leads to the fans. Now the fans run fast when ever I plug the harness back together. This happens regardless if the fan switch is plugged in or if the key is in the ignition.

Before the fans would not run after the key was removed even when the engine overheated.

Any ideas? I am hoping it is the switch.

Keith

[MyOtherRidesAVette]

Originally Posted by colonwq

Thanks for the updated images. My copy was black on black with random-ish specks of white.

I was able to unplug the wire. In order to get my hand in there, I unplugged the rear wire harnesses that leads to the fans. Now the fans run fast when ever I plug the harness back together. This happens regardless if the fan switch is plugged in or if the key is in the ignition.

Before the fans would not run after the key was removed even when the engine overheated.

Any ideas? I am hoping it is the switch.

Keith

Did you test the switches as suggested. Did you test the fans at the first speed and the second speed as further suggested? They either work or they don't. I guess I'm not understanding. The fans do not run on power switched through the ignition. Do you need the complete system wiring diagram? I just put up the page showing the fan swicthes.

[Design]

man this is why I feel better about bypassing the factory fan control system.

As an alternative (it is not for everyone) you can bypass the factory control system by buying an aftermarket electric fan control kit. This is available at your local parts store.

It will come with thermostat probe (either one that sticks between the fins of the radiator or one that inserts into the upper radiator hose) and a relay with the associated wiring. My relay had a line for the thermostatic probe and one for the AC signal and could power two fans.

My probe was one that went into the upper radiator hose with an adjustable temperature setting.

For the AC signal I pulled the plug on the compressor and after some testing determined it was the #1 line that needed to be tapped.

If your fans work but they are just not getting proper signal then this is an option. I did it in combination with replacing my burnt up factory fans with aftermarket versions. The down side is that my fans run for a little while longer after I turn off the car because they continue to get the "on" signal from the temp probe. In my case, both fans come on at operating temp or with the AC on.

May not help but thought I would share.

JB

[colonwq]

Here is how the tests went:

Initial conditions: engine cold to the touch, no key

red to red/white: both fans run
red to red/yellow: no fans run

My previous testing was invalid because I unplugged the 4 wire connector to the FCM and the 4 wire fan power connector in order to make room for my hand. These two connectors can be reversed resulting in the both fans running fast without the key in the ignition.

Keith