My husband left his lights on at work. When I went to go jump him off, he put the - cable on the + side and vice versa. He lost all power to the inside of his cab. The head lights will still come on, but that is it. Daddy checked the starter and the alternator and they seem to be fine. My dad is a mechanic and he is stumped. What else could have happeded, a blown fuse or relay, a wire shorage....I need some ideas?
Main fise is most likely blown, Although, we could probably better help you if you gave the information as to what make model and year vehicle you have.
Searcher1
Sometimes when polarity is reversed while jump starting you can burn out a section of the wiring harness, usually around the starter solonoid relay and/or alternator. Since the headlights are direct wired outside of the charging/ignition circuits they can still work while there is no power for any other circuits. You need to check fuses as suggested in Searchers' post and if no bad ones are found then start with voltage checks along wiring harness(s). davidj92
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