I have an Alpine head unit with an Alpine XM tuner box under my console. On cold mornings, the radio works for about 1 1/2 hours and then the head unit screen flashes "Loading" and will flash loading for 30 minutes straight. Turning off then on the radio for about 30 seconds will get me about 3 minutes of play time on XM, and then it flashes loading again. I have no trouble most of the year, even in August when it's 100°F plus and 72° dew point (it's not the humidity that kills you, but the dew point!) I've called XM and Alpine and they just scratch their heads. It seems to be related to cold mornings. (running the heater on full and heating up the truck 'till I can't stand it anymore, doesn't seem to help)