I have a 2003 a4 3.0 and the cooling fans go on and off when the car is not running. They are supposed to do it if the car gets too hot, but mine do it until the battery dies. I noticed it seems to do it more often the colder it gets outside.

 

-bump-

 

anybody have any ideas... I've checked sensors replaced relays.... need other ideas

 

Well, if you've swapped out relays and sensors, the only thing left is short. I dont have the wiring diagram, but check every thing to ground with the ignition off. You could also look for a fusible link or thermal fuse somewhere inline and check that. What I'm thinking is there's a short making the fans run constantly which heats up either a thermal fuse, fusible link, or even a relay, which then opens turning off the fans. When this part cools, it closes and starts the cycle again. Happening more frequently the colder it gets outside supports this. Make sense?

 

thanks... that does make sense. I'll have to look it over see if i can find anything.... What a pain in the butt a couple cooling fans can be.....

 

I agree... I once had a prob where the fans wouldnt turn on at all... Had power to the fans, relays worked, etc, etc... turned out to be corrosion at the splice for the fusible link. Took along time to finally find it.

 

Fan control module. Not an easy repair either. The connector isn't plug and play, it has to be manually wired. I had to do a bunch of these at the dealer. Its the module by the radio with the big *** wires going into it. I would have the dealer do it for you IMO.

 

I thought the fan control module was the silver box at the front of the engine bay just above the fans??? And I heard only to replace that if the fans don't work at all...

 

It could be silver or black, and no you don't only replace it if the fans don't come on at all. I belive there is a TSB on the issue now which outlines the repair.