r/Cartalk • u/jhwalk09 • Dec 31 '23

Safety Question When a jumpstart goes wrong?

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Neighbor tried jumping my wife’s ‘06 Nissan Altima, we left it for 10 minutes and came back and the cables had melted through the headlight of both cars and some of the bumper. I wasn’t there but thankfully they stopped their car and were able to disconnect the cables without incident. We noticed after there had been mice living in around her engine from the mouse poop, minimum the last two weeks. What causes jumper cables to do this? Something a rodent may have chewed? Definitely an issue with my wife’s car. Our poor neighbors have a newish midsized suv. My wife has also had constant issues starting her car, even with a new battery I got a year or two ago. Anyone seen this before?

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u/Oh_MyGoshJosh Dec 31 '23

My guess is the clamps were switched around

3

u/Eric1969 Dec 31 '23

Wouldn’t that be immediately very obvious? Like from the sparks shower as soon as the clamp touch the terminal?

2

u/Bachooga Dec 31 '23

Immediately obvious and I find it hard to believe someone would ignore it for 10 minutes. Considering the other info OP posted, sounds like a fault. Maybe an intermittent short to ground somewhere from mice nesting.

I'm not sure how many people here have ever jumped a car before but your clamps don't generally burn your finger prints off and wire gauge and the amperage it can handle also depends on the length.

Positive to positive, ground to chassis. Things shouldn't get hot and there shouldn't be a shower of sparks. Leave it on just enough to start the other vehicle then disconnect and drive the now alive car around the block a few times.