I cross the cables while jumpsatrting my truck...Now what?


OK Ok I know this is the number one no no when jumpstarting your car, but I was really tired and was trying to jump start my truck and crossed the neg and positive connections. There was a small fire at the grounding wire that is connected to the battery & fender and it’s now melted and split in two. I’m not sure what damage it crossing these wires causes or what should I do next? My truck is a 1992 Ford F150


What you see is mechanical damage and you just fix what you see. That is the easy part. It may also have caused damage to electronic parts of your car including any or all of the computers that control the engine safety equipment radio etc.

Good Luck.


Thanks for the response. I feel like a complete dumb a** for doing it in the 1st place. I relapce the wire and should I take the Bat in to bne checked and chareged before trying to start it again?


It depends on how the circuit was designed. Best thing to do is after replacing the wire, continue checking for other damage. Since the switches were off (right?), damage should be restricted mostly to the always-on circuits. Check the fuses first as those are the cheapest to fix.


Don’t feel bad. I had a Sunbeam that the dealer was working on. They left the lights on. So they removed the battery and recharged it. They showed up with the car after about 30 minutes. I drove off and after a couple of miles the battery light came on. I drove back with the light getting brighter all the way. Well they have put the battery in wrong (a 1965 Sunbeam was a positive ground car). Then ended up giving me a new batter, starter, generator and regulator. They also warranted all electrical parts for one year.


If you didn’t have the key on, you should be ok. When a reverse voltage is applied, the alternator acts like a short. The output lead of the alternator has a fuseable link and that may also be open. Sounds like the battery cables were about shot anyway before this happened and acted like a fuse. This may gave protected the other stuff. Be aware the alternator may have a diode that is now bad. If you had the key on, this can damage the computer. Later years of Ford have a diode that prevents the ECM relay from closing for just this purpose.