1990 Mustang LX ground wire
When I sit at a redlight, my voltage gauge drops way down. I have conclauded that this is most likely a ground issue because I have changed the alternator, battery cables, and had the battery checked. I was checking the ground behind the radio and found a black wire and a red wire, both both bolted to the bracket above the radio. I noticed that they sparked when they bumped together, checked them and the red wire has almost 11 volts on it. Any ideas on what this wire is or why it would have a voltage on it?