When I start my truck up (03,3500) the voltage gauge is at 12-13, then it bumps up to 15-16 after 15-20 seconds at idle or immediately if i start driving it, also most of the time only the driver side window controls work, and once in a blue moon they all work except the passenger side window, it will go down but usually not up, any help would be much appreciated ive already been driving for a year with this problem, also i have a plow installed but the problem was there before i installed the plow

 

the voltage is normal, its because of the grid hearters, the windows i'm not sure about, but it sounds like a possiable failing window regulator

 

Grid heaters.

Probably a switch. My 03 does that, sometimes if I hit the door panel and try it it will roll up. I just haven't gotten around to replacing it yet. I just leave the windows up