I recently purchased a 2013 Sierra 2500 and noticed that the voltage is showing about 10v on the dash. I went and tested with my multi meter and its about 12.6 on the battery and 14.4 while running. I'm trying to figure out what to check next to see what would be causing the low voltage to display. When I turn on the truck, the gauge is pretty slow to get up to the 10v mark and doesn't really move when I turn things on. The previous owner changed all the lighting and added several aftermarket lights to the truck, so I'm wondering if maybe something was wired wrong, but I'm not sure where to check first.
