bendavis2

My battery died yesterday from my driver-side fan staying on all night. I didn't notice until it was too late. After getting the battery charged, and recognizing the problem, I decided it must be a faulty thermo-fan switch. The relay seems to be working just fine. But here is the rub:

If I turn the car off after a short drive with the engine relatively cool, the drivers-side fan stays on (at the slower speed) even though the engine is cold and the key is out. But if I put the key back into the ignition, and turn the key to the on position (but not to the crank-and-start-the-car-position), and then rotate the key back off, then the drivers side fan turns right off.

This is making me think that there is something besides the thermo-fan switch that may be causing the problem.

I'm about to pull the thermo-fan switch and test it in hot water just to make sure it is working, but would love to avoid draining the system and pulling the switch if anyone thinks I should be looking elsewhere.

Thanks in advance for any wisdom or guidance.

gux944

It happened to me too.A bit different,I turned of the engine and sometimes the fans(both of them at slow speed) kept running....running...never stopped until they drained the battery.try clark`s garage test for the hole fan system.I changed the thermo-fan switch and no problems since than.I`m sure that`s it in your case too even with those strange things,what`s yours doing.and about the switch,I used one from a 97 Audi A6,is the same.

951mcomm

+1 on the thermofan switch. You dont have to drain the system. You might lose some fluid but when you take out the old just have the new one ready. not bad. you will have to bleed the system either way

John_AZ

If you do not have the specific thermofan wrench, it is easier to remove the fans to get access.

Replace the thermofan switch with a similar temp. Do you know if yours is (65C-uncommon) 75, 82, or 92C (102C-uncommon)? 2 prong. Should match it to your thermostat temp.

The plastic tank threads strip very easy. JB Weld is your friend.

These are the temps for an '83 944 early. Update signature line?

GL
John

tblofsky

my fan switch decided to go out the other day also. after a year and half the new switch dies again. The fan should stay on low speed for 30 seconds or so just to ex-spell some of the hot air in the engine bay. Mine will also shut off if i put the key in and turn it on and back off.

bendavis2

Sorry about the lack of Signature. I'm not a subscriber (sorry! ;-0) and I always forget to write my sig line out. I'll be replacing the switch shortly and will hope it solves the problem.

Ben

1983 Porsche 944 n/a