i hooked up a new head unit today and it sounds great but when i plug in the dmm i dont get any voltage. and when i do get the proper voltage i need (14.1) the head unit is almost all the way up and then the voltage jumps from 12.2 to 15.3 to 14.2 to 11.2 and so on. what am i doing wrong? the head unit is on flat and nothing is up just like its supposed to be and everything else is wired up correctly. the amps power on button isnt lighting up either, however the amp works. the head unit is a pioneer deh-6300ub. any advice???