I just bought a 2001 C4 with the factory fixed aero wing, mounted inside the engine compartment lid is a fan that appears to not be running. I have stood in the back of the car with the car warmed up and I can only hear the fans up in front running. I have had the hood up with the engine running and this fan isn't turning, can anyone help me with trouble shooting this before I bring it into the shop and find out this is not a problem

I am I mistaken and this fan is part of the air intake system and not the cooling?

Sorry for the dumb questions!

 

This is a good question
It could be a few things, if its not coming on at all it can be a bad connection at the plug, a bad relay, or maybe a fuse. I am not sure if this will work but have the car running and have the AC on the highest fan setting and the lowest temp, it should come on.
Now to your question :The fan in our cars is a very smart thing, when the car is running it does bring in cold air, but when the car is off it revereses and sucks hot air out.

 

The engine compartment fan DOES NOT suck air out of the engine compartment at anytime. It is designed to draw air into the engine compartment. The purpose of the fan is to cool the compartment after it reaches a specific temperature. After the engine is off, the computer monitors the temperature of the compartment for 20 minutes and will turn on the fan is necessary.

You can test the fan by unplugging the 2 wire connector from the sensor on a fully warmed engine. The fan should start immediately and turn off immediatley when reconnected.

 

1999Porsche911 I don't think I am following you on the 2 wire sensor? I have four wires going to my fan two go to the lid light which should have nothing to do with the fan and two wires that provide power to the fan! If I unplug the fan 2 wires there should be no power, hence no fan, and I plugged it back in and same no fan? Thank you for your help on this I don't want to pay the stealer for something simple if I can....

 

There is a sensor between the intake runners on the right side of the engine. A 2 wire connector is attached to this sensor. Remove this connector as stated above and your fan should start immediately.

 

Pics? I am now wondering if mine is working as I have *never* heard it fire up ...

 

1999Porsche911 Great help I was able to get the fan to turn on this way so I most have something wrong with the temp sensor....again thanks for your help!

 

Don't assume that the sensor is bad. The fan is not programmed to come on until something like 180F or if your coolant temperature reaches a high point. I forgot the parameters of the sensor, but when I have time, I'll find them.