hi there I installed a new headunit in my 04 cavalier using the scosche harness with chimes and switched positive. The strange thing is that when I swith the key on or to acc the radio works fine, but when I start the car it turns on plays about a second worth of sound and shuts off. The only I can get it to work is if I let my car run for about 20 minutes shut it off and start it up and it works fine, but once the car has been off for about an hour the process starts all over.

it's a problem with the switched wire which leads me to believe you bought a bad harness

I thought so too I'm on my third harness. A friend of mine was told at a local shop called soundmasters that he needed to wire a relay into the harness do you know anything about this?