installed a pioneer DEH-P5800MP head unit and put db6750 in the front doors of my 02 avalanche.
Next I bought a C400.4 Carbon Series 4/3/2 channel Amplifier. When I first put it in I was getting engine noise through the speakers. So I thought it was maybe the ground wire and I unbolted it and used gas to clean the undercoat of the chassis then used sand paper and rebolted the ground. That didn't work so I started checking the RCA wires and when I would unpluged the front speaker RCA cables the noise would stop so I switch rca cables and unplugged the cable I thought was bad. I proceeded to ajusted the amp using only db6750 in the front doors man do they rock!
Today I put a new RCA cable on the rear speakers and Installed a brand new set of mmc6500 momo in the rear doors and when I went to test them my engine noise came back. Frustrated I put a jumper wire from the body ground to my chassis ground and that did not work either. If I unplug the either one of the RCA cables the noise goes away.
what should I do next ?
Thanks in advance ,