My fan turns on, even before I start the motor when the key is in the accessory position and runs during my drive and until I remove the key.

Reading through some posts in this forum, I decided to buy a used Fan Control Module. When I went to install it turns out that I cannot find it anywhere.

It is not located on the radiator at all. I followed the harness to the passenger side (US) in the area of the running light.

Does my car even have a Fan Control Module? Are they hiding it somewhere else?

Could it be that there is another issue other than the FCM? The other day the fan didn't turn on at all and I thought, whew, it's fixed...Until I turned the A/C on. Now it is stuck on all the time again.

 

Tell us your car details...

 

2003 S-Type 4.2

 

There's a fan module but they tend not to fail. Controlled by the PCM and that's where you should probably be thinking: why it wants the fan on.

But as you have a module I don't see why you couldn't try it if it's a match. Mounted on radiator somewhere as I recall but you can grab the workshop manual to check.

It also has all the electrics so you can check for any relay(s) that may be stuck.

(You can get just the elec. guide from www.jagrepair.com if the full workshop manual is awkward for you.)

 

Thank you!!

Do you think purchasing an ECU off of ebay would just be plug and play? Or do things need to be reprogrammed?

The Fan control is definitely not located on the radiator fan housing. I followed the harness to under the right underside of the headlight assembly.

The manual says "ENGINE COMPARTMENT, RH FRONT, REARWARD OF RADIATOR". What I see there is a coolant reservoir tank and below that looks to be some kind of solenoid.

I guess I will have to crawl under there again and take more stuff apart so I can see what is going on in there.

 

About a year ago I had issues with my cooling fan , and presumed it was the controller . I purchesed a finned alloy fan controller for the correct year s type , but it turned out there is two different types ! The v6 uses the alloy external controller mounted on/in the fan shroud and the v8 has a differant fan with the controller biult in to the motor ! Any way I traced my problems to a large squar loom connecter directly behind the right hand fog light behind the front bumper . Witch was full of water , cleand all the green muck out with contact cleaner and a wire tooth brush and wd40ed the hell out of it no probs since . Mine was eather on full or not at all ! And ocasionally would blow the fuse , so may well be a different issue , but still worth a look !

 

+1 on examining the wiring loom behind the front bumper.

Also check the coolant level as low coolant level, or if the system has air trapped, can cause the radiator cooling fan to remain on.

 

Thanks Guys!

It is interesting, I did follow that harness back to the connectors. I jiggled them around the other day looking for that module and gave up. When I started up the car the fan was off...until I turned the A/C on. Then it was stuck on again. I will clean up that connector and let you know.

Coolant is on the max line, so good to go there.

Next will be learning how to flash the ECM. I have that "Lurch" issue too and am hoping to remedy that soon as well. It never lurches when I come to a complete stop...but who does that, right?

 

Well I found the connector that supplies the power to the fan and pulled it apart and it was totally free of corrosion. As a test I left it unconnected and the fan did not come on.

So the issue has to be before that connector. JagV8 suggests PCM is to blame. Is the Power Control Module part of the ECU? I was trying to find the part on Ebay, but only saw ECM/ECU's there.

 

99.9% it will NOT be the PCM. They are fantastically reliable and can cope with abuse.

You need to troubleshoot everything else, such as harnesses.

 

have you tried to hard re boot the car ?

 

Finally got this fixed. I took it into the garage and it turned out it was the fan assembly (built in module). They diagnosed, I fixed. They mentioned the new fan should be re-programmed, but I haven't done that and not sure that I will.

The fan cycles now as it should.

I am pretty sure I am loosing a bit of coolant, I can still smell it a bit a month later, so probably will do a pressure test on that soon.