mke4now

Hey guys!

Been reading these forums for years, finally in need to post my own question!

I have a 1987 944. Was having trouble with fans staying on after car is shut off. I replaced both the thermoswitch and relay 2 years ago.

Ordered new relay, did not fix it. So I am planning on replacing the thermoswitch today.

Plug the relay in, fans go on no matter what temp.
So of course, plug in relay before i start to drive. Pull it when I shut it off.

Here is the issue however:

~Went into a Fast Track and had the oil changed yesterday.

Now, when I plug the relay in, the fans don't turn on automatically (after unplugging and plugging back in).

This is even when the car is hot. (ie. Been driving car for 30 min or so in 89 degree weather. Pulled relay, fans went off. Plugged it back in, fans did not turn on.

So it seems that when I plug the relay in, it doesn't turn the fans on right away, but does after I drive it for a while.

I am mainly confused, because it had all the symptoms of a bad thermoswitch (from Clark's Garage) until after I had the oil changed.

This is why I am so worried right now. I leave for a trip tomorrow to Chicago, so I was planning on doing my brake pads and replacing this thermoswitch. I will have to do valet parking, and I don't want to depend on the valet dude to remember or know how to pull the relay when he parks my car!

Any quick response would be greatly appreciated guys, thanks!

Notes:

Replaced battery 3 months ago, numerous jumps (perhaps screwed with some electrical?)

Have been pulling and plugging in relay for a few weeks, driving multiple times a day. (Could have shorted something out?

Relay is brand new.

THermoswitch 2 years old.


~** Any help ASAP would be great! Need to know if I will have to setup a car rental today! **~

mke4now

~~

odonnell

It sounds like the thermoswitch is still bad, you should replace it? Maybe you damaged one of the relay plugs in the fuse panel by all the commotion.

mke4now

Thanks for the reply!

so relay plugs, like where the relay plugs into the fuse box right.

anyway to test it?

mke4now

One other thing, probably important! The fans do not go on when ignition is on! I don't think this is normal is it?

snb13

Mine was acting similar recently. It was a bad thermofan switch.

cruise98

The fans only work when either the thermo switch is closed or the A/C controller is calling for fan operation. You have an intermittent problem and the only way to know for sure is to do some diagnostics. You will need a flashlight, multimeter and a short length of jumper wire. I wrote a long diagnostic you can search for that will help you sort it out. I have seen new relays go bad in a short period of time, so it may not be the thermo switch.