I have woken up the past two days and went out to my truck to only have a dead battery i get jumped and it fires right u go to work no problem and am fine through out the day. I just installed a new head unit a Sony XAV-70BT and its the first unit i have put in with a constant 12v i know why its there but i think it is draining my battery. any ideas would be great

 

Pull the radio fuse before you let it sit overnight to see if that's the problem.

 

I unhooked the radio harness and it didn't die.

 

Bingo....

 

all radios have a constant 12v, sounds to me like you have the ign + and batt + wire backwards. i know on all aftermarket harnesses ive dealt with, the red wire is ign and the yellow is batt, were as on the radio its opposite.