Auto dim mirror always dark

[CarlPalmer]

I have a problem with my rear view mirror. The mirror is always dark. It does not have any buttons on mine, just a slider.

Reading online, I see that the mirror darkens when it receives power. So my mirror is always receiving power. Many times I heard that when these go bad, just to get another one, but I really don't want to go to the trouble of a puller parts place, and they are damn spendy online.

Anyone have any thoughts about a troubleshooting technique on it, or thoughts on what the problem may be?

 

[willindsay]

What year is the mirror in?

To test your theory of if it's always receiving power just find the plug and disconnect it and see if it goes back normal.

Since it has no buttons on it I really doubt there is much you can do to fix it. Unless you are willing to take it apart. My guess is that something on the circuit board inside has gone out. You might be able to repair it if you're fairly competent with soldering on circuit boards.

I would check with some of the forum vendors here for a good used one.

 

[SoNic67]

Mirros have 2 or more power leads:
- one continuous for the ones with compass (helps store the magnetic zone number)
- one switched off with the key (activates the rest of circuits, including dimming)
- one wire from back-up lights, to cancel the dimming when backing up (not all models).
- dome light connection (if model has integrated lights - turn on with door opend)

For Gentex mirrors:
Wire: Color Connection
Black: Ground Wire
Red: +12V supply switched by ignition
Yellow: +12V constant power (battery)
Brown: Connected to +12V dome light circuit

 

[CarlPalmer]

That is awesome! Thanks, I think I can do a little testing of it now.