It sounds like the power cable can not handle the load of amps put out from the alternator when the car is running check the voltage when the car is driving it could be that the alternator may be bad also, and caps are a waste of money unless you have 12 farads per 500 watts
i have a kenwood ddx7015 in my escalade it is wired to my bose factory stereo just got some humming out of my right side only anyone seen this before i think it is my interface that went bad ???
