Fan problems are killing my battery!!!!!

I have a '87 N/A 944. Recently I noticed the fans were running more than usual when the car was off. Originally I thought it was because of heat down here in florida. But It does it at night, when the engine is completly cold. Now they run so much it kills my battery! Ive found away to avoid the problem, by taking out both fan fuses whenever the car will be off for more than an hour but its only a temp fix.
ANY HELP WOULD BE GREAT!!

Problem Info:
While car is on fans run normal and engine stays cool

When car is turned off fans run for 30sec then shut off like normal

However then they keep turning on & off thruout the time the car is off. Sometimes running for minutes on end & sometimes not even starting all the way.

Any ideas on what I should check or if anyone else has had this problem that can help, id greatly appreciate it.
thanks

The radiator temp switch may be going out. It screws on to the radiator itself and has two large brownish wires hooked to it. The next time it's running while the cars off and cool, pull a wire to see if the problem's there.

Good luck.

like 83-944 said, i had the same problem and it was the fan switch (in rad) temp switch fitted in engine block. hope you sort it.