My friend is putting my cd player, sub, and amp for me. He took my car after school cuz I had bball practice. Anyways, I called him after, and he said that they couldn't get the cd player to turn on. Any suggestions? I have the harnesses with me if that helps any to see what they did. He thinks that they did it right but could it just have been a bad ground?

 

even if the ground was bad - the unit would most probably still work. Try using a new harness or maybe try testing the positive terminal with one of those voltmeters. by the way......did the radio on the head unit work atleast.....??? - or were u referring the cd player as the unit as a whole??? Did the led's on the amp turn on???? - test to see if any voltage is going through the power on lead ( the blue wire)