RMsALFA

The quickest check if all is well is to see if you can rotate the rear mount fan easily by hand (with the car off and cool, of course).

bud4ya

Perfect will check this so this would be the fan mounted close to the fire wall? Not the fan upfront (Nose Of Car) correct?

RMsALFA

The fan that sometimes jams is the small 6-8" dia electric unit on the engine side of the radiator, offset slightly to the passenger side (US spec cars). It's next to the clutch driven fan and attached to the radiator. It should turn freely by hand.

The fan up front of the radiator cluster is the one that gets fail-safed to full speed upon failure of the fan control module.

bud4ya

This is what I found, I checked the smaller fan behind the rad and it seemed to be caught on something. So I reached my hand up in and you can see in the pic I attached what was binding it. Once I pulled the piece of rubber out the fan spins freely. Does anyone know what this rubber piece does and if it in fact goes in that housing somewhere?

The next thing I found is when the AC is on meaning light is off on the econ button the fan that is running is the big fan in front. It will run for say 30-45 sec's shut off for about the same then kick back on. Is this normal? When air cond is off the big fan in front does not run.

Thanks

RMsALFA

Yes - that is the standard failure mode I was speaking of. That rubber strip is a vibration damper that falls out and jams the fan. For information, you can search various Audi forums by using terms such as "air raid siren fan".

USUALLY, what happens is the fan control module FAILS due to the high current draw of the locked fan. The backside fan is usually fine but will no longer run when freed due to the failed control module. Since the module has failed, the front fan is commanded to it's highest speed whenever the A/C is on and will be quite loud. If working normally (when the coolant is not too hot), the fan will be almost silent with A/C enabled.

The control module is relatively expensive and supposedly can be replaced (if you have small hands) without putting the front in service position. The car will not be damaged with a failed fan control module but you will be annoyed by the loud whining fan whenever the A/C is on. My fan locked in exactly the same way and destroyed the module. I ran it like that for almost a year before replacement, in service position, while changing the alternator.

bud4ya

Thank you very much and I have some more questions. Now will the smaller fan that the rubber piece was caught in will that fan need to be replaced? Also the rubber piece I took out should I buy a new one and re install? Or when I replace this module the rear fan and front fan will then work like they should?

Now for the failed control module are you saying if I search under "air raid siren fan" I will be able to see some write up's on how to replace? Sucks because just a couple months ago had it in service mode replacing the alternator.

If I do not use the AC will be fine? Just worried if fan is not working right the car may over heat

Thank you so much for helping

bud4ya

So after some more research tomorrow I will put power to the small fan and make sure that fan works. Will do the same on the big fan to see if it will work properly. If it works with me providing power to it then the fan control module is bad I am assuming. I will also check the fuses I just need to find where the fuses are. Not sure if they would be in the car or motor compartment. Any other thought or ideas. If some comes up with a good DIY yourself for replacing fan control module please send it to me. I found only one

Thanks

RMsALFA

I can only speak from my experience, although it mirrored what I had read somewhere a few years ago.

On my car, the control module acted as a "fuse" and saved the fan from damage. After removing the trim piece and replacing the module, the fan worked to spec. I did not reinstall the rubber piece that jammed the fan to begin with.

I think the electric fans only work as a back-up to the clutch driven fan on the engine. Even with a bad module, I believe the front fan would turn on at full speed if extra airflow was commanded, but I'm not certain. What I do know is I drove the car for well over a year with a bad fan control module. I never saw any noticeable increase in coolant temperature and it does get hot here in the summer.

bud4ya

I put power to the fan from battery and it works. Checked all fuses on side and underneath steering wheel all tested good. So it is control module. Need to see if there is a write up or vid on how to replace. Looks like hard part is getting to it. If anyone has vw part #is that would be great. I have the audi part #

Thanks for everyones help and i will not re install that rubber piece either that looks like a pain

johnkk

Don't have the part number, but the module is on a vertical frame member on driver side near outside edge of radiator. If you drop the belly pan you can see it. The bottom bolt is easy to get out, but the tip is a pita. Getting the top bolt back in is even worse. I was lucky and finally got the bolt started. In hindsight, should have pulled the bumper cover for better access.