I've got a question for people with the Auto-Dimming rear view mirrors in their trucks. Can you tell when your auto dim is working? My F-150 has an "auto" and an "off" button but the mirror does absolutely nothing and has never worked since day 1. I do have the green light that is lit but have never seen any change while driving even with bright lights behind me on the road. I'm assuming I have a defective mirror. Any help would be appreciated.

Thanks
sting123

 

I didn't think the mirror worked either until I tried turning it off while someone was driving behind me with lights on, then there was a difference. If you try that and still don't notice a difference, take it to the dealer.

Good luck
Marty

 

Shine a flashlight into the sensor. It's easy to tell if it works.

 

Yea it's very noticeable when it's working.

 

I can tell if I'm looking in it at night and then I turn on the interior lights, I will become dimmer. (than I already am )

 

It's really easy to tell when mine's working. It goes from the "can't see much" mode to the "can't see @#%*" mode. You can try covering the sensor (which faces back) to test it. By the way, as far as I know, the mirrors in the '04 and '05 are different. Mine has no provision for turning it on or off - other than blocking the sensor.

 

Thanks for the tips everyone. I checked the mirror every way and it is dead. I never noticed it not working because it was broken when I bought the truck.