i have a amplifier for my highs. I connect to amp to my car for the first time and i got power, but when i started driving down the street it cut off. i looked at the amp but the power stayed on. Then i took it to a shop and had them look at the amp and it was working, he tested all the channels and got sound, then i placed the amp back in my car and it was working again. So i checked the rca by plugging a portable cd player to it and it still didn't work. I really don't know what is going on can someone please tell me what it may be. I read some other posy and they all siad to check the ground, I'm going to do that but need some ideas what else it may be}