Audi's Dad

I have a 97 Cabriolet, Recently I realized my fans were not operating properly. I have done some research and troubleshooting and am confused by the results.
1. I removed the connector from the switch and was able to turn the fans on both speeds.
2. I have replaced the fan switch with a new unit.
3. the fans both work when the A/C is on
The confusing part is they don't seem to operate when the engine temp. goes up. Also they do not come on after shutting the car off. I am not sure that this car/ model has the second option but would expect that it does. Any insight to what this might be would be appreciated. Thanks in advance for you response, you are my go to source and seem to have endless knowledge, which for an Audi noob is invaluable.

Rusty Spokes

There is some confusion in the parts catalog concerning the radiator fan switch for our Audi cars. The confusion is caused by Audi..as they indicate the correct part is a 191959481A a 95*/102* thermo fan switch


The fan switch which is on the cold return side of the radiator. By the time the coolant gets to 95*C on the cold side of the radiator..it is very very hot on the inlet side and the temp gauge will indicate a hot engine.

The correct part is 251959481K a 87*/93* fan switch. With this fan switch the engine temps will operate normally.

Be sure and get the fan switch from a reputable supplier. I have gotten some bad or counterfeit switches..reboxed single fan speed switches and incorrect temp settings on the duff switches.

Try and use a Wahler 251959481K if you can. Be sure it says Wahler on the plastic and indicates a 87*/93* on the brass body. See the attachment for the location of the Walher stamp.

Our Cabriolets do not have a after-run on the radiator fans..so the fans not remaining on with the key off is okay.

The radiator fans on low with the A/C on is not connected to in any way to the radiator fan switch. That feature is controlled by the A/C being on and power 12v to the resistor board under the left front of the car.

Audi's Dad

R.S. Thank you so much for all the information that I needed and more than I could have hoped for. I checked the specs for the switch that I recently purchased and found the 1st switch was active at 90c and the second at 96c. I will be following your advice and purchasing the Wahler. I live in a mountainous area that experiences temps, over 100F in the summer months so it is critical that the engine cooling system is optimal. You are a credit to this site and I do appreciate your effort