the radio always shuts off when you start a car. if it is hooked up right. i have a 96 grand cherokee and my radio always shuts off when i start the car. thi ignition switch re routs the power from the radio when the key is in the start position and re powers the stereo when in the run position. and my 90 cherokee was dong the same thing and mine was the neutral saftey switch in the tranny i had to slam it in park sometimes so i could start it.