I have a 2012 Camry SE and ALL Interior Lights have a very dim flicker at best. So dim that I can't see or read anything inside the car at nightime. The dash lights are fine and the navigation display is fine. But front and rear dome lights and courtesy lights on the doors only emit a dim flicker. This occurs with door open and with door closed while manually turning them on. Also occurs with car on and off. I don't think it's a fuse because then I wouldn't even get a dim light, I'd get nothing. Not door position switch issue because lights come on when they're supposed to, just very, very poorly. Don't think it's a ground wire unless every light uses the same ground... again, all interior lights malfunction. Can't be bulbs, they wouldn't all go out at the same time, would they? Could it be battery or alternator issue? I don't get any indicator that battery is low but I plan to test it, alternator, and regulator tomorrow. I think with this model, the regulator is in the alternator. Any suggestions appreciated. Thanks!

 

Start by checking the voltage at the dimmed lights.

Do the headlights dim at idle?

 

The headlights don't dim at idle...they seem fine. I'll pop a cover tomorrow and check voltage. What am I looking for? 12 volts or less? I did do voltage check on battery. 12.5 with car off. Only 13.5 with car on. That's seems low, I thought it should be a little over 14. Not much spike while giving it a little gas. After turning car off again, only 12 volts. Alternator might be a little weak but how perfect does the system have to be to operate tiny bulbs?What are your thoughts?