Probably not a real usefull thread but I was curious how the auto dimming rear view mirror works. It is neat technology and I am looking for a quick explanation of what makes it work.

CoKTM

I don't know if Gentex is the manufacturer for the mirror in the GM trucks, but they do make auto dimming mirrors. Here is the explanation you are looking for:

http://www.gentex.com/auto_how_nvs_work.html

That sure looks like my mirror. I'd say that's probably who does make it.

SmoknDmax, Thanks for the link. Now I have another bit of info to fill one of the many voids in my brain. Ya just never know when this stuff may come up in conversation.

CoKTM

Note in the "how it works" explanation that it dims only if the rearward-facing sensor is getting blasted with light. This is why the mirror doesn't dim unless you have a vehicle pretty close behind you. If find its operation pretty useless and wish I had just a stupid manual day-night mirror.

This tuck is full of wizzie electronic things that could have been done right. You only find out they make things more difficult after you've used them for a while.

I found out through a small impact between my mirror and my garage that the exterior mirror has a gel in it also! Here's a piece of advice: If you ever break the auto dimming mirrors DONT just keep going about your business and fix it when you have time. THe gel stains the black brush guards, the black rubber molding around your mirrors, and the black strip molding on the side of the truck. Just a piece of useless info for ya.

On the 2003 and newer models they have a the wireing for the driver side dimming mirror that I believe is black. I may have fubared, but when I hooked it up to 12v power it seemed to have burnt the mirror.
I have the 2002 model and hooked up a set of 2003 fully loaded mirrors to it and had to do some wire configureations. I am not sure if the wire for the dimming option was suppose to go to the rear view mirror wire and then get trigered. It seems to be ok, it just has a slight bue/green tent to it.