Im installing an after market head unit in my car.. I have to keep the old head unit in the car because of my keyless entry so I went to circuit city to buy the harness that has the spliter to connect both the new and old radio. When I pluged in the old radio to the harness it doesnt turn on. I used a tester light and the wires are hot so I think its a problem with the old radio. It worked just fine yesterday. Is there a fuse in the old radio that I could have blown, I hope I didnt fry the old unit, I dont know how I could of though.