Years ago I had an accident with my Austin Healy, positive ground English sports. car. When I got it back, everything worked, starter, generator, and heater blower. However the radio wouldn't work. I took the car to a radio service center and they tested the radio and it was fine. They determined that the garage had just connected the battery charger with negative ground and that was it. The garage bought a new battery.
Paul & Helen
2002 Winnebago Journey DL
1999 Jeep Cherokee toad
Yellow Lab, Jodie, Chocolate Lab, Coco , and Lab/Golden mix, Sandy.