Subject: self dimming mirror
Question:

My 94 Diamante LS has a self dimming mirror is stuck on dark (dimmed). It was working yesterday. it stays dark even with the car off.

Answer: Steve,
There is an electrochromic element in the mirror (which is similar to a liquid-crystal display in a digital watch). If the sensor that activates the element is malfunctioning and the mirror is always at it's dimmest setting, then you may need to replace the entire mirror. I do not know if you can just replace the sensor, but I don't think you can.
Good luck!