My battery was dead when I came out of Dizzy World tonight. when I got a jump start and drove home my alternator sat just above the 12 volt mark. That disturbed me because it expected it to be nearer to 14 due to the drained battery, but the lights never dimmed and the battery had a 12.37v charge when I got home. I checked the battery terminals with a meter and with the engine running I was showing 13.75 volts, so it is charging. What really disturbs me is that the cooling fans were running and never stopped even 1/2 hour later. It appears that they were running when I left the car and drained the battery down. I pulled the circuit breakers for fan 1 and 2 individually and heard the fan relay click and the opposite fan go into hi gear. It did the same when the opposite breaker was pulled. Also when the AC was switched on the fans ran faster (or an additional fan came on). Also the fan relay box was prettywarm as well. Correct me if I'm wrong but it sounds like the radiator temp switch may have failed and is causing the fans to run continuously. Is there anything else you can suggest that may have caused the fans to run like this?

 

You are on the right track. Swap out your auxillary fan switch (radiator), and it should take care of your problem.

 

A web site that discusses this switch in a FAQ format says use a 30mm deep socket to replace the switch. What is the size of the socket? also, is it necessary to drain coolant from the radiator to below the switch to replace it? Are these switches available from NAPA, Carquest or any other retailer besides Porsche ($)?

 

You do not need to drain any coolant if you are quick enough. I can't remember the size off the top of my head, but 15/16 or 24mm sticks in my head for socket size.

 

I wish I knew socket size for sure since I have to buy specificallythe right one since all my tools, except the ones I bought for this car, areat my other house. Any help? I'm having fun pulling fuses while the car is parked, just so I can drive it. I'd forgotten how much fun 20 year old German cars can be.

 

Well, if you don't already have a 24mm deepwell, then you might as well go out and buy one anyways, cause you will use it alot.

 

i just replaced my fan switch and i needed a 29mm deep socket. just some info.

 

Just so I know, did you drain the coolant and if not how much did you loose?

 

i didnt, but i lost maybe 2 liters when i took the switch out. like porschedoc says, if you do it fast enough then you wont loose much. i had access to a lift and didnt have to remove anything. woohoo! just to be on the safe side, bleed the coolant system and fill the overflow to the max line.