Peter Corrigan

I think I recall this happening to me last winter. Basically I shut off the car, take the key out and you hear the humming of the passenger side fan loud as usual. Just to check if my battery is supplying other things I try opening the window, turning on the radio, and turning on blinker signals and thankfully none of those worked (as they shouldn't when the car is off). I went online and found that a number of people have had the same problem.

I began to get worried that it would drain my battery so I unlatched my Battery's Positive wire And taped it down, I also taped around the thing you hook the jumper to. Finally the god forsaken fan stopped.

A few hours later I had to go down the block to pickup something so I put the Cable back on the positive battery, saw a few blue zaps, locked it in and left. The fan was put on immediately. Here is where it gets weird, on my way back when I parked my car in the driveway and turned off the ignition, there was no more fan - IT WAS OFF?! If cars were anything like Computers i'd say I hardbooted it and reset the error but I never heard of this fix....any idea how this could be? It's so strange!

mel_t_vin

Normal operation...PS fan may continue to run after shutting engine off depending on input from temp sensors.

If you intend to electrically neutralize a car, disconnect the negative terminal from battery, not the positive.

mikey_audiogeek

Often caused by a failing thermostat switch on the radiator. But yes, it is normal for the radiator fan to run on for up to 30 seconds after engine shutoff.

mel_t_vin

Mike, no matter how warm your coolant is, your fans only continue to run after engine shut off for ~30 seconds? Wonder if that's an S2 thing?

My fans will continue to run for minutes after shut off. Have never actually timed them, but suspect they run for at least 5 or 6 minutes.

Tiger03447

When you disconnect the battery, please take the negative cable off first...and reconnect it last...if done with the positive cable, the current surge may fry the diodes in your alternator..also there are less arcs and sparks when you do the negative last...

mikey_audiogeek

When the car is cold, the fan doesn't run on.
When the car is hot, the fans run on for up to 30 seconds until the thermo switch in the radiator says "enough!".

When the switch starts to fail, the fans run on for longer, until the switch fails completely and you end up with a flat battery...ask me how I know...

mdnt08

I got annoyed at it running long with the car off so I installed a electronic fan control with a sensor that is powered by ACC power.

sweetskillsrk

The thermo fan switch was one of the first things that went wrong with my 944 (I keep a spare on me now). My fans usually run about 1 to 3 minutes tops on a really hot day. Common problem, but an easy repair. Just drain some coolant, take out the switch (1 1/8 socket), and put the new one in (make sure to use a new fiber washer/gasket too, don't try to reuse or make your own, it'll just leak). Also, when torqueing the switch, err on the side of too loose than too tight, I cracked the plastic on the radiator and ruined it cause I tightened it just a LITTLE too much. Don't make the same mistakes I did, good luck Peter!