Help identifying wiring, W220 Wing Mirror

[PJayUK]

There are four wires that connect to a block connector that in turn connects to the mirror glass. The middle two are both brown and connect to the glass via a pair of contacts on the middle right hand side of the rear of the glass. The outer two are striped pink-red and black-pink and connect to red and black wires that also connect to the glass but to the bottom and top edges of the mirror under the plastic backing plate. I am getting a steady 14V on the two central brown wires but nothing on the two outer wires. I was wondering if anybody would happen to know which wires are which? If I can identify the heating element of the glass it would help me diagnose whether its getting power or not.

Thank you.....

 

[adee]

Have exact same question, but on a w203. Did you ever find out which wires are which?

 

[PJayUK]

Yes, the two central brown wires are for the heater the two outer are for the auto dimming. I ended up buying two cheap ones from a guy on ebay and making some slight mods to the connection. Works a treat and although I dont have the dimming feature (never saw the point of that anyway) my mirrors are toasty and warm!

One thing to remember when your testing the connection is that on mine they only say 12V when the engine was running.

PM me if you want info on where I bought the replacements.

 

[adee]

Thanks,
I have an auto dimming mirror from ebay, which dimmed as soon as I connected it. It's been disconnected now for three days and hasn't yet cleared...

I think it's fubar. I've got 14 volts on the two central wires and a low voltage on the outer ones - looks like it's wired the wrong way round, and now my mirror is probably toast!

Your post at least helps me make some sense of it. I'll let you know if I need replacements.

 

[PJayUK]

Mmm depends. Did you buy it from Poland by any chance?

 

[adee]

Nope, sourced in uk, but is LHD (I'm working in Italy at present). Part No is 211 810 03 21. Definitely odd though, that the connections on the mirror seem the wrong way round, ie. outer wires go to heater element, central wires to dimmer.

Will give up and buy a non dimming replacement me thinks.

Am saving for possible command replacement...