Ihave a 2005 chevy 2500hd LS Duramax,allison 4x4 ext cab sb and I live in Phoenix ,i leave the truck parked in the sun some times and when I do the compass and the temp wont work when you start the truck and you cant turn it back on untill the truck interior cools down . if it is on and working when you park the truck in the shade than it will come back on at start up automaticly .my brother's 2005 avalanch works all the time no problem .

Also being in the Valley of the Sun, I have never had that problem. I would guess you need a new mirror. I have had other display devices where the display disappeared when getting hot, only to reappear after they cool down.

I would take it to the dealer asap to get it fixed, or at least confirmed. They will most likely want to "see" the problem before attempting a repair. I think it will be easier to reproduce now, before the monsoon clouds arrive and shade the windshield glass.

Mine would turn off and back on whenever it wanted. I brought it in to the stealer and they said they have had a few with this problem in the past. Not common but they replaced it in 30 minutes or so and I was back on the road. You may have just gotten a defective one. They should replace it no problem.

Jeff