Possible bad thermo-fan switch?
 

The cooling fans have started not coming on at all. Could the thermo-fan switch be the culprit. I know it can go bad and make them always run... had that happen last summer.

It's worth a shot. Could get lucky and just be a lose connection or broken/shorted wire. My car started to do some overheating tricks last summer. I repaced alot more than the switch, but I'm pretty sure that was the culprit. Someone had mangled an early fan switch onto my late 944 and that was most definatly the problem. Mine would either run alot when the car was shut off....like for hours and then it wouldn't kick on enough when the car was running and it would almost overheat every time. I put a new water pump, low temp thermostat and low temp fan switch and didn't have a lick of trouble (with that) afterwards. If you go low temp fan switch I have read that you need to use a low temp thermostat otherwise the fans will be overworked since the thermostat and fan switch would be set for different temps/cooling cycles. G'luck!

take the plugs off the switch and jumper them.... if your fans run.. then it's the switch...

From Clark's GSM: http://www.clarks-garage.com/shop-manual/cool-01.htm

thanks ill try that when i get a chance

I thought I had the sam problem with mine a few weeks ago. Do check out the Clarks trouble shooting. That way you can tell if it is your fans, relays etc. Luckly mine was just a ground issue with some other electrical problems. But thats how you learn more about the car!

nope it was the switch... changed it and now its fine