MY truck rear view mirror and driver side, side mirror adjust automatically to the bright lights of some ones head lights. The passenger side mirror does not anymore. I can remember if it ever did to begin with. If it did, how is it fixed and what exactly is the mirror doing to begine with.

I'd say the lighting sensor might be bad, but thats just a guess.

I dont think the passenger side dims... just driver and rear view.

the passenger mirror never did dim. it is only the drivers and rear view mirrors that dim. i have seen this comlaint many times at work, being a gm tech. i have had people swear the other side used to dim. then you show them in the manual that it is just the two mirrors.