my fans don't turn on

guinnastysassy · 10-13-2003, 11:27 AM

my electric fans don't turn on at all. the car runs hot when driving slow but at highway speed it is ok. is the fan switch the same for pre/ post 85.5 is it a switch or relay. i left my manual out last night and my akita thought it was food(he will eat annything!!)could it be the fans themselves? what are the chances of them both crapping out at the same time???.

ds475 · 10-13-2003, 11:44 AM

mine aren't working either... i'm trying to get to the bottom of it...

NKN84944 · 10-13-2003, 11:45 AM

I had the same problem about 2 months ago when it was extemely hot and I was on my way home in traffic. I definately had to shut the car down several times, I hope you had better luck when yours went out. I just had to replace the cooling fan relay which is located under the steering wheel. I was able to find it easily just using the 84 electric diagram on Wilk's website http://frwilk.com/early944/al. I hope this is the same problem you have because it took me a whole 5 min and 10 bucks.
Nate

Roger Hall · 10-13-2003, 05:37 PM

Try turning on the A/C in my 81 924 the A/C switch bypasses the temp switch and turns on both fans. If both fans come on then it is probably the temp switch. If not try jumpering the contacts on the relay board to test the fans. I think later model 944s have one relay for the A/C and the fans. IIRC its a very expensive relay. I doubt that both fans would go at the same time.

Porsche944 · 10-13-2003, 07:34 PM

For early cars like your '84, the fans run in several "modes" depending on the status of the ignition, A/C, and the temperature switch in the radiator.

First, both fans should run at high speed with the ignition and A/C on (engine does not have to be running).

Second, one fan should run at slow speed when the ignition is off and the radiator is "hot."

Third, both fans should run at high speed when the ignition on and the radiator is "hot."

If the fans run with the ignition and A/C on, then the fuses, relays and fans are good.

If the fans run with the A/C and ignition on, but do not run when the A/C is off, the ignition is on, and the radiator is hot, then the temperature switch in the radiator is bad.

An easy way to test for a bad switch is to disconnect the wires at the switch and short them together. If the driver side fan runs at slow speed, turn the ignition on: Both fans should run on high.

If it turns out the temperature switch is bad, go for a low temperature switch. Pelican and several other vendors have stock and low temperature switches.

BTW: The cooling systems in these cars are designed such that the fans are not necessary at speeds above about 35 MPH unless the A/C is running.

bearone2 · 10-13-2003, 09:18 PM

what does "btw" mean

guinnastysassy · 10-14-2003, 02:35 AM

by the way..... it is the temp switch, would it do anny dammage to just run them off an accesoryline?i want to remove the ac annyway

Porsche944 · 10-14-2003, 04:36 AM

Running the fans continuously doesn't really make any sense.

As I mentioned earlier, at speeds above about 35 MPH the fans are not necessary. In stop and go traffic the temperature switch in the radiator will cycle the fans and keep the engine within it's normal operating range.

Replacing a faulty radiator switch is much easier and more reliable than hacking up the wiring, and if you're really worried about cooling, install a lower temperature switch.

guinnastysassy · 10-14-2003, 07:18 AM

i don't understand why my car is still overheating!!!. i removed the thermostat and ran the 2 wires that go to the switch connected. also have new waterpumo, not reman. all of the hoses are new and have only water and waterwetter in radiater. what else could cause the car to overheat???????? it does it just driving in the neighborhood @ 25-35mph

guinnastysassy · 10-14-2003, 07:20 AM

oh and i ordered a 70degree switch, i thought it would have been a lot more expensive, like everything else

SoCal Driver · SoCal Driver's Garage

Your radiator is cloged.

You have a leak keeping the system from properly pressurizing.

guinnastysassy · 10-14-2003, 08:08 AM

when the car overheats the only place the water comes out is the overflow oil is ok, where else could it be leaking?? how do you tell if the rad is clogged, is their annyway to unclog or should i just replace it???

Dark Skies · 10-14-2003, 08:39 AM

You need to reverse flush your rad - drain the coolant into a bucket for reuse, disconnect your rad pipes, stick a hosepipe against the usual flow and wash that crap outta there. I expect the procedure is covered in the Haynes manual at greater length.

Roger Hall · 10-14-2003, 04:57 PM

Are both fans on? Are both fans moving alot of air? Are both fans turning in the right direction? The fans should be pulling air thru the radiator into the engine compartment.

guinnastysassy · 10-14-2003, 07:11 PM

the fans where moveing in the right direction, i just finished swapping them w/ the fans from the.5. flushed the rad, nothing came out but i got soaked!

Dark Skies · 10-15-2003, 02:22 AM

Hmmm. Bummer!

I know this will come across as Dark Skies Master of the Bloody Obvious but ...
have you checked the appropriate fuse? I have no idea why but Porsche use the cheapest, nastiest fuses and fuse holders going and they are a constant source of hassle on my car.

The fuse may look unbroken but the connecting edges often oxidize and cause them to fail. Try pulling it, cleaning the connector and sticking in a brand new fuse. Don't forget to discon. the battery first.

I think this must be a regular thing with 944s because I remember Porsche World printed a Q&A in which the fan fuse holder came in for special attention. It seems that this holder often overheats and the recommended fix is to wire in two holders in parallel and use two fuses of half the original value. That's what I did on mine after my fuse started playing up.

Has anyone else heard of this fix? Whenever I mention it people seem to think I'm talking out of my arse.

guinnastysassy · 02:10 PM

i will deffinatly look into it. if it is a fuse the fans wouldn't work? if i takre the 2 wires off thge fan switch the fans work

Porsche944 · 10-15-2003, 08:10 AM

OK let me get this straight: If you take the wires off of the fan switch and short the wires together the fans work? If you do this with the ignition off, does just the driver side fan run at slow speed? If you do this with the ignition on BOTH fans run at high speed?

guinnastysassy · 02:10 PM

with the ignition off just drvr side on @ low, with ignition on both @ high

Porsche944 · 10-15-2003, 11:40 AM

OK. Fuses, fans and relays are good. Temperature switch in the radiator is bad.