I'm trying to install a Kenwood radio into a 2000 Chevy Prizm. I bought the correct wiring harnesses and wired everything up, but it's not working right. The radio only works if I unplug and then replug the wiring harness. Then I can turn the car on and off a few times and everything seems fine. If I leave the car off for a few minutes though, the radio wont turn on again until I unplug and replug the wiring harness again. Any ideas what's going on?