Thom

Bump.

The PO of my turbo removed the low speed resistor pack and shorted the wires.

To me that means that the fans should run in high speed everytime they are triggered by the fan temp switch (92/102°C) on the radiator, BUT when they are triggered they only run in high speed when coolant temp reaches 102°C - highest white mark on the coolant temp gauge in the dash.

I tested the fan relay by jumping the connector to the fan temp switch in the harness, it worked fine.

If the fan temp switch was faulty, I understand that the fans should be running all the time, but it's not the case. It's just that I never see the fans running before coolant temp reaches 102°C.

What am I missing?

Bri Bro

Sounds like an open wire to the resistor packs, look at post 6 of the thread for measurements.

Thom

Thanks Brian.

I actually corrected my message as it didn't make sense, it was wrong at the end.

The problem is that I never see the fans running before coolant temp reaches 102°C, even though the wires for the resistor pack (which is not there anymore) have been shorted, which means the fans should be running at high speed as soon as coolant temp reaches 92°C (or am I wrong on this?).

Is the fan temp switch at fault?

Bri Bro

Yes, it could be the temp switch. A quick way to test it is to unplug the temp switch and connect the low speed (92C) temp connector terminals together. With the resistors shorted, the fan should go to high speed. Be careful, the fans will run on low speed (in this case high speed with the resistor shorted) even with the ignition off with the temp switch jumpered.

From Clarks garage
http://www.clarks-garage.com/shop-manual/cool-01.htm

Thom

Thanks.

I did this test and the fans kicked in at high speed in both cases, so I suppose the fan temp switch is faulty.

(I'm not sure I understand how the fan temp switch is made and how it could fail this way, but this is another topic).

I have a new switch ready, will replace it.

Brian, thanks again for your feedback.

Thom

So yes, it turned out the fan temp swtich was faulty.
Replaced it with a new one et voilà, fans run at high speed as soon as 92°C

gregeast

I love Rennlist and the Rennlist community precisely because of threads like this. This is a fairly arcane problem and yet not only was the OP able to track it down within the space of a day or two with help from Brian but another lister was able to resolve a problem as well (not to mention countless others in the future who find this thread). You think a guy with an '87 Ford Taurus has ready access to this kind of information?

Well done all!

Landseer

Not only that, Greg, but I'm sitting here on the garage floor in Richmond VA, about to tackle the same problem.

Thanks to rennlisters who contributed. And based on search, Brian B has been on top of this, helping for years.

Oh, and while we are tossing around accolades--- awesome avatar^^

Bri Bro

Thanks

It is always refreshing to read good comment in Jan, most of the cars are parked and people get a little grumpy this time of year.