Fan constantly running at level 2 and very loud. Normal?

Hello,

I drive a VW Passat 3B TDI (AFN) with 81 kW and Climatronic.

When I turn on the air conditioning, the auxiliary electric fan behind the radiator automatically starts up on the first setting. So far, so good.

After about 30 seconds, the fan immediately switches to the second speed setting, and then it makes noise like a combine harvester. It only runs quietly on the first setting again when I drive faster (v > 50 km/h). However, when I stop at a traffic light or drive into a parking garage, the fan switches back to a faster and very loud level 2, and people look at me.

The phenomenon is independent of the outside temperature. It occurs both at 15°C and 25°C, even when the engine is still cold. However, this only occurs when the air conditioning is turned on, which otherwise provides full power (the air conditioning system was recently serviced)!


Is that normal?

How is the fan speed regulated, specifically how does it switch from level 1 to level 2 and vice versa?

and/or

2. the electric fan on the 2nd. How loud is level?

Hi,
Is that normal, that...

How is the fan speed setting adjusted from level 1 to 2 and vice versa?

and/or

2. the electric fan on the 2nd. Level, how loud is it?

The regulation you described seems perfectly normal to me. Both my 1Z (manual AC) and my AAT (Climatronic) systems operate in the same way.
The only thing that should be investigated is the fact that there is no temperature regulation adjustment based on the outside temperature in your system.
Perhaps the refrigerator fins are heavily soiled?

2. Yes.