I have a 2002 Dodge 3500 with the cummins engine. I have a weird problem. The heater and air conditioner control works fine. Its the tempature control that I am having trouble with. When I first turn it on it blow the selected tempature. But when I apply the brakes or hit a bump it changes to heat with the selector still in the cold position. I can turn the selector switch to the off position and then turn it on again and it works fine until I apply the brakes or hit a bump. Has anyone else hadd this problem? Also I have looked online at the plastic dashborad caps they make for these trucks. Has anyone used these? Thanks for your help!