Aftermarket radio problems
 

I'm trying to put a new radio in my 84. The old one was not original and the factory harness was cut up. I can bench test the radio from the battery and it comes on but I cant get it to in the car. I have both constant power from a thick red wire and ignition power from a yellow plus a ground. Could the security system be giving me problems? I'm lost and jvc isnt all that helpful.

Your ignition wire may not really be hot with a load on it or you don't have a good ground. Try tying both the radio red and yellow wires to the car's red wire and see if it fires up. Also, just as a test, try using the cigarette lighter's outside ring as a ground.