Both mirrors are adjusted using a switch in the left door trim. The mirror surfaces in cars with the "winter package" are additionally heated when the rear window heating is on. If there is no reaction when the mirror adjuster is activated, then:
Execution order
1. Check the fuse first.
2. Then remove the switch and check according to the instructions (also in this chapter).
3. If the switch is OK, remove the mirror glass to gain access to the servo motor connectors (chapter Body parts).
4. Is there voltage at the contacts of both servomotors with the ignition on and the switch activated, and is the ground connection OK?
5. It should be taken into account that depending on the direction of rotation of the servomotor, the pole of the voltage supply changes.
6. Is the voltage supply OK? Then only the motor may be faulty. Replace it.
7. You can temporarily adjust the mirror glass by pressing on it with your hand.
8. If the mirror heating fails, check the conductivity from the glass heating switch according to the electrical diagram.
[This publication is borrowed from the resource: audimanual]