Date registered: Oct 2011
Vehicle: S500 2000 (W220)
Location: Melbourne, Australia
Mentioned: 0 Post(s)
Quoted: 23 Post(s)
Hi all, I've now had success with this issue too.
I removed the mirror cover assembly by gently pulling forward from the bottom of it. Once you can slip a thin blade type tool through the gap between the mirror cover and the visor itself, push it up against the clips (there are two) one at a time to release the clip from the visor. Once both clips are released, the mirror cover will slip off (downwards) easily.
At this point, I believed I was going to have to split the visor, as I knew the microswitch was the likely culprit (the only other possibility was disconnected/faulty wiring in the visor). However, a forum post elsewhere said that someone had success by spraying contact cleaner into the microswitch.
Thinking there would be no harm in giving this a try, I did, and sure enough, after a few sprays of the contact cleaner and a few clicks of the microswitch with my finger, the switch was once again actuating the light when pressed. Success!
The only other problem was that the mirror cover itself wasn't staying up quite high enough usually, to keep the microswitch depressed. The mirror cover has a plastic tab on it (which has "Li" or "Re" pressed into it depending whether it's the left or right side cover) that actuates the microswitch when open.
What I did was "build up" the thickness of this tab by using some electrical tab placed on the tab.
Also, I repaired some cracks in the plastic bevel of the mirror cover (these usually form around the top of the mirror cover, where the metal bracket is that hold the cover in its open position.
When reinstalling the mirror covers, the top clips should be inserted (slipped into) into the visor first. Then gently press the lower part of the mirror cover into place, one side at a time, into you feel and hear that the clips have snapped into place.
It's a great feeling knowing you have repaired an issue, albeit a minor one, for virtually no cost instead of buying expensive replacement parts. Thanks all for the advice, I never would have thought a faulty microswitch in the visor would be the culprit!
NB: My visors still don't extend towards the rear of the car when unclipped from the roof as some have stated they can - mine either don't have that feature (I have an early W220), or the mechanism on both sides is totally seized. Due to the risk of ruining the visor both functionally and aesthetically, I doubt I will try and look at fixing this.