Was that fuse blown? Tail lights and dash lights both have circuits that branch off and go to the original radio, one to dim the display when the head lights are turned on and one to tell the display how much to dim. Very often radio installers will measure the resistance on the wires to figure out which one is the ground wire. Both of those lighting circuits WILL measure very low, like a ground wire, due to the many bulbs on them. If the installer used one of them as the ground for the new radio, that light circuit will be shorted to ground through the real ground wire and / or the antenna cable. One potential clue to this mistake is the radio will not play properly if you turn the head lights on and turn the dash lights to the full brightness setting. It doesn't matter that those lights aren't working, but it will matter which incorrect wire they used.
Sep 21, 2012 at 2:46 AM
