Is the AHK (Anhängerkupplung - trailer hitch) actually installed in the S6 Plus, or not?
EDIT: This is a copy from someone else; I am not the author, but it worked very well for me.
Reset the control unit and retrain the learned values.
Remove the ignition key if you haven't already.
Disconnect the battery and wait for at least 30 minutes.
After at least 30 minutes, insert the ignition key and turn it to the "on" position!
Connect the battery and leave it like that for 10 seconds - Battery connected and ignition key in the "on" position!
Start the engine without giving it any gas, and then do nothing else. Let the climate control run without turning on any lights or anything else – just let it run. This should run for at least 30 seconds.
Turn off the engine after at least 30 seconds of running!
Turn the ignition back on and wait for 10 seconds.
After 10 seconds, restart the engine as mentioned above, and let it run idle for another 30 seconds.
After 30 seconds, turn off the engine, remove the ignition key, and that's it.
Have fun!
EDIT 2: By the way, you can very nicely disassemble your climate control servo motors and verschandeln the slip rings from the carbon brushes, and they will function like new again

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