engine fan drains battery

[davieg]

i drove to work this mornign in my 944 cabriolet like usual, no problems, went to go out for lunch and the battery was dead as a dodo, i called a local mechanic and he says it may be the fan relay in the fuse box at fault. once power was suplied to the battery, the engine fan kicked in even tho the car had been sat for 4 hours. is this going to be the only probable cause to this or could there be something else keeping the fans going when they aren't required as they drain the battery unless i disconect their relay. it seems strange it's started 1'st time no problems since i've had the car and all of a sudden, this has happened. anyone got nay idea's?

Dave

[GreenV8S]

Don't know your car but I assume you have some sort of otter switch plumbed into the coolant system, which triggers the relay. So the problem is most likely to be a diff otter switch, or a duff relay, or a wiring fault between the two.

[steve 944t]

This is a very common fault on a 944 and is nearly always caused by a faulty thermo switch in the rad. It is located on the right hand side of the rad (as you look in from the front), about half way down. Only about £20 for the switch but is a bit of a fiddle to get at.

Steve