Br3nn4n

Hi guys,

I just picked up my first ever Porsche, an '86 944 N/A in Guards Red. It's in pretty good shape, needs some things fixed here and there, and a good coat of paint (although for a 27 year old car, it's in pretty damn good shape!).

The engine, transmission, clutch all seem to be in great shape. The PO said he got it from a family who had passed it down from kid to kid over the years. Dash is pristine. Anyway...

I've been having a problem with the fans running ALL the time when the key is in Accessory or On. It has been really bugging me, but I figured I'd get it sorted out soon. Then, I was driving yesterday and noticed how quiet the car was (strange) ... then I noticed the oil pressure was a tad low (below 2 bar) and the temperature was at the 3/4 high mark. Unfortunately, I HAD to drive it to get to work but I kept a VERY close eye on the temp and turned it off in traffic several times to prevent overheating.

The fans weren't coming on no matter where the key was or how hot the engine was getting.

I checked Clarks Garage to track down the problem and followed the test for the thermoswitch / relay. Or, I tried anyway. It turns out I have nothing plugged into my thermoswitch on the radiator!

I can't find the cable to replug / test it. Can anyone help? Where does it snake from? Would this explain my fans always being on?

Thank you all for your help. I can't wait to get this car in the best shape I can.

-Brennan

V2Rocket

the leads would be two small push-on spade connectors on separate wires, not a plug. they are small so they are probably lost in the bundle somewhere, they snake underneath the drivers side frame rail around the swaybar area.

without the switch though the only way the fans should run would be if the AC switch were turned on. both the low and high-speed circuits run through the thermo switch, but the AC switch has a bypass circuit to run the fans at high speed

Br3nn4n

Ok. The A/C switch doesn't stick on when I press it. Just pops back off. I'll try holding it and see if they come on. Here's a pic of the part I'm talking about that's missing:



The cable they're holding is what is missing. I just have an empty socket.

V2Rocket

Ah, your car has the later style fan switch then if it has three prongs. At some point in 86 they changed from a 2-prong switch with just spades to a 3prong with a plug like the picture.

Br3nn4n

Yessir! Post-February 1986, I believe, they changed it? (From what I've read.)

So I tried it with the cooling fan relay both on and off, and in both instances the fans turned on (both of them) using the A/C switch. It seemed like they were on low, although I wouldn't exactly know since they've been running fast and LOUD all the time since I got the car.

So what's next? And any idea on where that three prong snakes from?

Thanks for your help!

Br3nn4n

Any ideas anyone? Where should I be looking for this mysterious cable?

Br3nn4n

Could someone possibly just run out to their car and take a photo facing downward towards where their cable is plugged in and mine isn't? I would really appreciate it since I cannot find the d*** cable.

Br3nn4n

Ok, I'll be quiet after this post, since I feel a little stupid. Another 944 owner came out and took a look and pulled the whole airbox out and found it hiding under there. Plugged it in, but they're still not coming on.

If anyone else if having this problem, let me say this, since it may help. When I first got the car the fans were always on 100%, from the moment I threw the key into the first position. I had no idea why, but I think I now know. I already re-soldered all the points on the fan relay and that didn't help with the fans automatically coming on, although they work via the AC switch now.

Here's what I think was my situation. When my friend pulled the cable out he found a weird bent wire... "Huh that's weird." The PO had pulled the thermoswitch cable and jumped the pins to have the fans run full all the time, and at some point I hit something that loosened that jumper wire. That's my theory, anyway, and it makes sense I think.

Just for a little closure on my problem. I'm going to try out my theory tonight, see if I can recreate the problem. Though, I think I have it figured out.

StoogeMoe

Probably what happened is that the thermoswitch is bad in the radiator. Then the low speed fan ran all the time and drained the PO's battery down. So he said, "I'll fix that!" and pulled the plug. Then he said "Oh no! Now my car overheats in traffic!". So then he put a wire in to jumper the high speed fan so that it would run all the time (and thus wearing out the fans prematurely).

So be ready to change the thermoswitch and plug the connector back on. Then you'll be good to go. Don't you just love PO's and what they do to avoid to fixing the root cause of the problem?

Br3nn4n

At least they noticed it was overheating (I assume)! I still need to go out and actually test my theory but it seems like the most logical explanation, especially since they just randomly stopped ever coming on one day.

Weirdly though, with the plug plugged in the fans don't stay running when it's off. So I'm not sure on that note, but I still think that thermoswitch needs replacing. Anyone here in Riverside or nearby have one I could buy off them?