LFA951

My tech checked the cooling fan relay two nights ago and determined that it was fine, he said not to bother getting the new thermo switch, that he is going to jump the lines so that the fans will run on high when I shut it off as opposed to the low speed it's running on

JohnKoaWood

For all future refferences, fuse #11 blowing was the subject of TSB Group 9 # 8902.

And despite its effectivity being listed as 84 and 85, my 88 also needed to be done... have not checked the 87...

JohnKoaWood

I guess ultimately it is up to you, but I would rather have it working correctly than jumpered.. just my 2C.

LFA951

So I should get the thermo switch anyway?

JohnKoaWood

What is going to jumper?

If it is a bad thermo switch I would replace it (I also replaced all the coolant sensors, and the radiators in both my cars)

if you have a faulty sensor replace it, if it is a faulty relay, find a replacement for it... if it is wiring shoot yourself in the head because you do not want to have to f with the wiring in these cars....

ask me how I know this...

LFA951

How do I know if the thermo switch is bad? The low speed fans stay on for like 30 seconds after the car shuts off, even if it got hotter than expected on the temperature gauge, but it still doesn't cool down to the first line after shutting off...

JohnKoaWood

The clarks garage procedure, and the link to another thread on here both have troubleshooting guides to follow, they will narrow down the source of the fault (thermo switch in radiator, relay, resistors oir wiring).

ehall

Also, check the fuzes and relays. There is a relay, or fuze, (can't remember which but it's on the inside of the fuze box) that activates the second fan, and a separate one for the first. Check those out. It could be that easy and checking will take five free minutes.

LFA951

Thanks Ehall, I first checked the fuses for the fans fuses 10 and 15 and they were fine, I am getting a thermo switch for $20 and since the relay is fine we are going to start there, it's been on the car over 4 years now and my tech thinks it may not be working right snce it may have oil or corrossion on it from when oil got in it when I had the oil cooler seal leaking oil into the coolant..

ehall

cool. I was just out checking crap and it came to mind.

LFA951

Well, I replaced fuse #11 so now I have my dome light back, I pulled out the thermo switch adapter and cleaned the terminals with some silicone, put it back in, cleaned prongs on the relay and when I put the key in, the fans went on but not when I pressed the A/C button, they came on when I hit the defroster button below it!

JohnKoaWood

The AC button is the one to the RIGHT of all the other controls, over there all by itself... You hit the windshield defog button and the fans come on, that is a good thing..

FWIW the button above that one is the recirc button for recirculating air inside the car...

Fans running is a good thing!

LFA951

Thanks, it is a good thing, but they only go on with the defogger button you said on the bottom left of the two little square buttons, below the recirc button. Other than that, both A/C buttons the one on the console and the one next to hazard light are depressed, still the fans come on low speed, is the thermo switch what controls the high and low speeds, if so should I still replace the thermo switch?

JohnKoaWood

Yup, thermo switch kicks the fans on high when temp reaches turn on point! IIRC it is close to 175-185 degrees F!

DeWolf

Just had this exact problem. Pulled the plug and shorted the wires. Low speed fan and high speed came on. Thermo switch knackered. Replaced switch....all good.