[CodeWzrd]

I have an 2LT with the auto dimming mirror. I don't think I've ever seen the greenish tinge you normally see when the mirror is dimmed.

The left most light is on. I've turned it on and off at night while on the highway but I don't see any changes to the light.

How can I test this? Can I shine a flashlight at the mirror?

 

[ChevyMgr]

Is there anything hanging on or attached to the mirror blocking the front sensor (back side of mirror)?

 

[cottonseed]

I have an 2LT with the auto dimming mirror. I don't think I've ever seen the greenish tinge you normally see when the mirror is dimmed.

The left most light is on. I've turned it on and off at night while on the highway but I don't see any changes to the light.

How can I test this? Can I shine a flashlight at the mirror?

That light on the left is to let you know the rear view camera system is enabled. I found that out the hardway oneday when I accidentally turned it off and was going crazy trying to figure out why the rear camera wasnt turning on. The light on the right is for the onstar battery.

 

[jstpsntym]

To be honest, I don't recall my mirror ever dimming either. Well, between the dark tinting of all the rear glass and the ride height of the vehicle, I don't think headlight glare has ever been an issue for me.

 

[INNOCNT]

+1[/color]

 

[ChevyMgr]

You could test it at night time with the help of another vehicle being behind you. Put your vehicle in drive and have the vehicle behind you turn their brights on. Then put it into reverse and see if the mirror changes. By design when your vehicle is in reverse the mirror does not dim, so that you have the best view possible.

 

[bballr4567]

Use a flashlight to test it. Its probably working but you dont notice it.

 

[2010Nox]

I guess the one in my Sierra must be more sensitive because it mostly always dims, even though the rear facing sensor is now looking through not only the factory dark tint rear window, but two more dark tint windows from the cap on it.

As far as I have figured out there is a front sensor and a rear sensor. The front sensor requires a certain level of darkness (ie. no headlights shining at you & few or no street lights), and the rear facing sensor does require a certain amount of light shining at it.

You could try covering the front one and shining a light a the rear one. But remember it doesn't happen instantaneously and the tinting comes on gradually.