Have strange problems too.
My 06 Dodge Cummins Mega Cab will not allow the radio to come on when i do a cold start. If I let it warm up and kill it sometimes the radio will come back on and other times it will not. My amp gauge is all over the place too, it seems to be charging all the time. i have been thinking it might be an alternator problem or a bad battery. I hope dealer finds out what is wrong the charging systems on the 06.