Circuit City installed a new head unit.

And now the auto-dimming light doesn't come on...yet all the other rear view mirror functions are working.

Anyone have any ideas?

I don't believe it's a fuse as all the other rear view mirror functions have power.

Is there some sort of harness for the light sensor behind the stock head unit? Perhaps they unplugged it during the install?

 

If its getting +12vdc, the dim should work.

All dim functions are internal to the mirror/base AFAIK. Mine has comp & temp also. The comp is internal, the temp has an additional harness & sensor-connects to the exterior of the mirror at the 7pin connector, if its a Gentex.

Light sensor is in the glass side of mirror, needs the windshield side sensor dark to dim. Cover the front facing sensor with your finger then shine a light into the rear facing/dim sensor. That should dim it.

BTW, does your have "undim when put in reverse" function?

 

Thanks for posting my issue sscustom.

It doesn't have the undim in reverse, its just the regular scion mirror dim one (with homelink not cop and temp)
I guess maybe thats just the one they did for my 2005 tC ?

Anyway, the homelink buttons light up, the map light goes on but the auto dim doesn't.. also interesting is that the colored light (the dash light) doesn't stay on either. It goes on when you cycle through the options but when you let go of the map light (to set it) it goes away.

 

Interesting.
The problem is that the indicator light for it does not come on at all, no matter how many time the clumsy fingers push the botton.

 

ummmmm... i've rewired alot of stuff behind my factory deck. and i haven't had no problems with my auto dim. maybe take it back to the guys at CC and have them take a lookt at it. asking nicely will make sure ur well taken care of. i doubt it was the stereo install... but things can happens....