Cooling Fan constantly running
 

Hello all. I wanted to ask you all about something. My 2001 AR is running the cooling fan constantly, probably 80-90% of the time that thing is humming, and not only on the hot days. Is there some sort of sensor for this fan thing that might be faulty and making it run ?
Interestingly, I just had the car tune-up and services by AUDI, wouldn't you think they catch something like that ?

Is it your clutch fan or the electric fan? Do you have the ECON button turned on or off on the HVAC? If the ECON button is off then you will have the AC cycle on and off depending on what temperature you have it set for. If the AC turns on then the electric fan will turn on to cool the condenser.

My clutch fan is engaged constantly - PITA

If it is the front-side-of-radiator fan that is running on high, then the other electric fan, behind the radiator, is most likely burned out. This is a common failure and when the rear fan fails, the fan controller runs the front fan on constant high to compensate, regardless of temperature. The viscous fan on the driver's side has nothing to do with any of this.

Bottom line is that there are 3 fans. One is the clutch/viscous fan driven by the serpentine belt, located on the driver's side. It is "freewheeling", meaning it always turns when the engine is running, but if the car gets hot, it REALLY starts to turn.

Next you have the electric fan, used when the A/C is on, and it is beside the clutch fan, but located on the passenger side.

Then there is another fan, located in FRONT of the radiator.

So which fan is constantly ON?

Thanks for all the responses. I have narrowed down the problem (most likely) to be associated with the ECON and Air Conditioning. I will be monitoring this however because I do remember this problem going on during winter and spring time and that is when I am usually with ECON on. Above will help a ton for me to determine which fan it is, thanks a lot.