My wife has a 2004 Camry. It appears that the dimmer switch does nothing. Its located next to the ash tray on lower left side of dash.. I replaced the radio awhile back and you can not see it during the day. I bought what I think is a new dimmer but I can not figure out how to remove/replace it. Also might be linked, the back up camera is also not being displayed.

 

Is this the dimmer you are talking about?