I have a 1999 audi a4 2.8L quattro and just recently i have noticed that when my car is off that my a/c fan is running. it will intermittently turn on and off while the car is off. I have also noticed that it will run when my car is on, whilethe a/c compressor is off. It almost sounds like a jet wanting to take off. I just wanted to know if anyone else has experiened this before because i cant figure out the problem and i have replaced the a/c fan relay and checked fuses along with replaced my a/c and heater control panel unit and im still experiencing the same problem. The vehicle has been in the shop four times already and they cant seem to find whats wrong with it. also just to note that this has been occuring when the temps have been between -5 &15 degrees. any suggestions or help would be appreciated.

 

yeah, i use to drive a 99 vw jetta 2.8L that did the same exact thing. I would always have to pull the fuse out, and it was pretty convient because the fan fuses were right on the top of the battery. Don't know how it got fixed, one day it just stopped happing. GOOD LUCK! lol

 

Get your ecu scanned. There might be a fault code stored thatll point you in the right direction.

 

is it the AC fan or the coolant fan??

 

I think he means radiator/coolant fan
maybe not
But if it sounds like a jet plane thats usually the rad. fan.

 

move to a warmer climate..lol

no do what onepoint8tee said he is almost always right.

 

could be the fan switch and quite normal if its gone down ( the fan stays on all the time when driving ) to prevent overheating

 

i have checked while the fan is running and its not the radiator fan, its located to the left of the engine bay which i believe is the a/c fan. i have had the car in the shop and had the ecu scanned and it had no faults stored. i am also getting alittle interference in my radio when the fan kicks on and its a stock unit. it sounds like a cracking electrical sound through the speakers when this fan kicks on and off intermittently. i appreciate the advise and help, hopefully this can help.

 

thanks for your help everyone-it took alittle diagnostic time but it ended up being my secondary air pump relay and ac fan relay.