Oh man I need help on my cooling fans on my 944,can anyone help?


Hey guys,I barely just got back on since....a year or so,I gotta show my contributions.Listen I am in need of help.I have a 1985 Porsche 944 the early model and I have been stuck on the cooling fans for almost a year and I cannot figure out why they wont turn on while the engine is running.The fans will kick in if the engine is off and the key is on the on switch and the fans are kicking in on high,I am on a another forum called 944online but now i feel like i am being ignored and all I am asking for is alot of help.This is my project car for 4 years already and I am not ready to give up. So the changes I did to the cooling system was a new thermo fan switch by whaler,A new stant thermostat 80 degree,Relay for thed blower fan,and i believe the cooling fan relay works,the fuse is not damaged,the fans function,and i filled the whole engine up with water because i had no budget to buy coolant.I did every bit of work i can do,if i drive the car the water in the cooling system circulates as long as i am on a constant speed.Please help me out anybody,before I have to make the harsh choice to salvage it.(I hate retiring cars).


it will only stay cool if im driving thou,but all i know that'll just circulate the water from its own cooling system


RKC Wanderer
Do you have the wiring diagrams? your best bet would be to start at the battery, testing everything along the way for power/ground.


Pontiac Pilot
You said the fans come on with the engine off key on, but not when the engine is running, what about when the ac is on.

I am thinking your fan relay has crossed wires. If you have a circuit diagram, found in Haynes manuals available from amazon, bookstores and auto parts stores, to check your wiring is going to the right terminals on the fan relay. The fan relay works or the fans wouldn't come on at all, likewise for the fuses and fans.

Usually the fans run off a relay controled by a thermocouple switch which turns them on when the engine reaches a certain temperture and in some setups constantly when the ac is on.

In any case since they come on when the key is on but engine off indicates to me the possibility that wires on the fan relay are reversed causing it to turn the fans on when they should be off. They don't run when the key is off because of another relay or switched power from ignition on the fan power side. But I am just guesing, so get the color code wiring diagram and check to see if everything is wired riight, then check relay, then check for shorts.

If nothing else you can wire the fans to run direct whenever the ignition is on, or rig a manual circuit ,or build a simple relay circuit using a thermocouple or switch. No need to scrap the car over such a simple problem.