Ok first off I have a 1985 Cadillac Seville with some electrical problems. If you are in the car with the doors shut listening to the radio and you open any of the doors the radio goes out and resets itself to 1:00 and 1400 AM. I've checked everything I can and found that the problem is coming from the door panel lights, whenever those lights come on the radio display power goes out. Also, the courtesy lights that are under the dash by your feet never go on when you open the doors like they are supposed to. But if you push in the main lighter in the middle of the dash, those courtesy lights come on. The lighter never gets hot it just acts as an on button for those lights. So here's how everything is related. If you are in the car with the doors shut with the radio on and you push in the lighter, the radio goes out. If you have the lighter pushed in so the courtesy lights are on and you open a door, the courtesy lights go out. Even if you turn the headlight switch to the left to turn on the interior lights the radio will go out. So some how those three things; the radio, the lighter, and the floor courtesy lights are related and do not work together. Can some one please help me? Thanks

 

Have voltmeter and wiring diagram, will travel.

Look for floating grounds, here and there, in your wiring harness. Perhaps a blown fusable link?...but probably not.

Pick it apart, one appliance at a time, and look for teltale "half way voltages" that indicate your appliance is finding "virtual ground" through a second appliance, rather than "hard ground" as was intended by the designers.

If you don't know what I'm talking about, then find a helper who does.

Best of luck, and stay away from lightning storms and nuclear explosions.

 

Blown 20 amp "body" fuse.