Chris
The location of the dimmer switch is its biggest enemy. It has a large heat sink on the back of it, but no air flow over the heat sink. I drilled 2 5/16 holes in the top of the a/c register under neath the dimmer. Since I always have air coming out of the vent it creates an air flow over the heat sink. Very noticable change in temperature. At least half of my driving is at night, and some times 4 to 6 hours.