darrengj

The larger fan on my Cayenne will not stop running when I shut off the engine. I let the fan run, thinking it would eventually stop, but the fan kept running and drained the battery. I have pulled the fuse in the #1 location in the fuse box under the hood, just so that the fan will not kill the battery again. Any ideas on this one? I searched and it does not look like this is a common issue.

Thanks,
Darren

grohgreg

Nine year old car, I guess it's not out of the question that a fan switch could go bad. Can't help you with the physical location, but you might be able to trace the fan wire backwards. On those I've replaced on other cars, the thermal switch has been somewhere in the neighborhood of the water pump. Again, can't speak specifically to the '04 Cayenne S - but it's historically been a simple matter of unscrewing the bad switch and replacing it with a good one. The harder part is usually just finding it.

//greg//

darrengj

Thanks Greg. I just checked the cooling system parts diagram and it shows the temp sensor is on the back/passenger side of the engine. I am not sure if I can get to it without removing the intake. Darn.

grohgreg

That might be the temp gauge sensor. You're looking for the fan switch. First is a sensor/sending unit, second is a sensor/switch

darrengj

I don't see a fan switch in any part diagrams. Could the switch be integrated into the fan? I thought I had read that somewhere else, but now cannot find that info.

darrengj

Will look through wiring diagrams next.

911PERVY

Same thing happened to our 2004 S, I took out the fuse and ran the car for 18 months without it, never did the temp move above normal, sorry, it doesnt help you but dont worry too much!

Slow Guy

Usually the fan switch is going to be screwed into the radiator itself as the fan is intended to cool the radiator (contents). The temp at the back of the engine has little bearing on when the fan should run.

XR4Tim

The fans should not run for more than 13 minutes after the ignition is switched off, regardless of engine temperature. If one of them does, your likely culprit is the fan output stage, which is included as part of the fan assembly of each fan. The other possible cause is a faulty DME, but that's less likely.

hahnmgh63

After looking through the parts PDF I found one on the Waterpump for the 3.6 but for the 4.5L I only found the one on the back of the Cooling rail behind the engine, none shown going into the radiator so maybe it is a Multifunction switch. I've never looked at it.

deilenberger

+1 given the symptoms. Local mechanic friend had a P!G in for repair with the identical problem. It was the fan controller (only available as part of the fan assembly.. lotsa $$$.)

darrengj

Thanks for the help everyone. Looks like I will be purchasing a fan assembly.

ECS Tuning

We actually have two options for a fan assembly. One being Bosch and the other being OE. Click here for more information.

ALEV8

Mine just started this in the winter no less, running for a minute or so after I shut the CTT down in the garage. Never did it before, even in 115F heat in summer here in TX. Mine never runs for more than two minutes.

42empress

Happened on my RS4. It was a solenoid.