RESOLVED. Writeup is below:
If your mirror doesn't return after tilting for reversing, the "potentiometer" in mirror housing is not clean or has a bad contact. "Potentiometer" is a combination of "female" copper element (number 1, see pictures below) based inside mirror housing and plastic "male" (number 2, see pictures below) which is part of mirror glass. As you might have guessed, male travels between female contacts back and forth (I'm sorry, I always think about sex), so the mirror electronics "knows" exact position of the mirror depending on position of male part inside female part. If you are interested in physics of the process, you can read
this and
this US patents.
If the system works well, you can move mirror glass with your hand or with joystick and then press and hold "recall from memory" button until mirror returns to remembered position. If contact is loose you can get all sorts of problems when it comes to remembering and recalling exact position of the mirror glass.
Solution:
1.
Remove mirror glass. This is very easy. All you need is plastic stick. Don't worry -- you can't damage anything if your tool is made of plastic. Just pry it off -- the system is designed for easy removal of the mirror glass. Don't disconnect electric contacts unless you want to repair something else. All you need is to remove mirror glass so that it hangs on electric wires.
2. Clean plastic "male" if it's dirty.
3. Clean copper "female" if you see corrosion on it. Rub with sandpaper or with a thin file "inner lips" of the copper element where it contacts with "male".
4. Most important part. Take narrow pliers and squeeze copper element at the top and at the bottom. This will help copper "lips" to grasp the male part firmly from both sides. Don't press pliers too hard, as this will create excessive pressure on the male element. As a side effect of excessive pressure motors may have difficulty moving the mirror or you'll notice judder when adjusting the mirror.
5. Put glass back in place. It will just pop into place.
6. Sit into car. Adjust mirrors with joystick. Press Memory+1 to save current mirror position into memory. Move mirror with joystick or with your hand. Press button 1 until mirror returns back to saved position.
4. Start engine. Engage reverse. Mirror tilts. Engage parking position. Mirror returns. Problem resolved.
When you actually start doing this, you'll notice how easy and self-explanatory the procedure actually is. It will take from 30 minutes to 1 hour of your time.
P.S. I combined this procedure with installing
"aspherical" mirror for passenger side, which is absolutely cool for observing blind spot. For my UK-based car with anti-dazzle feature the part number is "8D0 857 535 H".
