Audi A3 8L Electrical Problems

Hello.
I've been using this forum as a guest for a while now, and I'm really impressed with what you can learn here. Whenever I have time, I read the posts.
Now, I'm having a problem with a vehicle that's exhibiting some strange issues.
My main problem is the V85 heating actuator motor. Is it complicated to replace this on this Audi?

"It's strange that there are errors in both the engine control unit (ECU) and the instrument cluster regarding the coolant temperature, because the ECU displays correct values, while the instrument cluster displays completely different, incorrect values. If I disconnect the connector from the temperature sensor, the values in both units don't change at all?"
The temperature gauge almost always shows around 80 degrees, whether it's cold or warm. When you turn off the ignition, the needle stays at around 60 degrees. However, during the display test with VCDS, the needle moves to all the correct positions.

First of all, I hope to receive suggestions and solutions from you regarding these problems.

Hello,

The coolant temperature sensor contains two separate sensors, one for the engine control unit (ECU) and one for the instrument cluster. It's often a good idea to replace it, as it can fail relatively frequently.

Regarding the flaps/actuators: Just check everything. As far as I remember, some of them were stiff on my 8L, at least the recirculation flap failed mechanically back then. The only thing to do is to disassemble everything to access them and then check them.

Best regards, Rainer.

Simmerring wrote:

My main problem is the V85 heating actuator motor. Is it complicated to replace this on this Audi?

You can access it using actuator diagnostics, and if everything is stable, you can even listen to it.
The panel located under the steering wheel and in the center console needs to be removed. It's the same design as the one in the Leon 1M. The lever is yellow.

The V85 will likely have a similar design for the flap actuator as my old Audi C4.
You can disassemble it, and then you'll find a kind of rotor inside that rubs against carbon brushes.
"In the 'rotor', you have 3 notches, and the contamination from the coal can cause it to give incorrect readings and stop working."
To put it very simply, and it's been a while since I built that.
I can't tell you exactly where it is located, but I don't know about the vehicle.

Okay, thank you for the very quick responses. The V85 actuator motor was/is broken. The main problem is the stiff mechanism of the heating system itself. I disconnected the actuator motor and then manually set it to the desired position (defroster). (You have to imagine, driving for 2 years without a defroster "and" with a faulty air conditioning system). Repair was not an option because basically everything was broken: the air conditioning compressor, and all the actuators are stiff.
And therefore, too expensive.
Accessing the side mirror motor was easy; you just need to remove the side panel on the driver's side, and it's right there. I'm not sure if it's that easy to replace, but it might be!

Regarding errors related to coolant temperature, I unfortunately don't have any new information at the moment, as the car is currently unavailable and the owner isn't particularly interested in resolving this issue.

EDIT by DBär: Duplicate post deleted