I have a 08 Silverado LTZ Crew. The radio is the Bose CD Changer w/o Nav. In mid December, when I would remotely start my truck in temperatures less than 10', I noticed the clock would reset to 12:00. This happened 4-5 times and then quit happening (It was not in the single digits).

I took it into my dealer for the washer recall and they couldn't find anything wrong.
This week is has been cold (Single digits). Last night I remote started and the clock reset again. This morning the battery was dead and I had to jump it. This makes me think it has more to do than the radio.

Any ideas????

 

The first thing that comes to mind for me is poor performing battery in the cold, I would have the battery load checked, if its okay then maybe consider adding a trickle charger or upgrading the battery.
And make sure nothing is being left on or plugged in that could be drawing the battery down i.e. phone or Ipod charger etc…

I should also mention checking the battery cable(s) make sure everything is tight, I don't know if the trucks have one, the Tahoe's don't, but check foran under hood light that may be staying on.