Jumping a car gone wrong help

I know very little about cars and need a little help.

I needed a jump this morning and called my apartment’s maintenance staff. He came by and started connecting his cables. I told him he should not connect negative to negative but he said it is fine. Heavy sparks flew and my negative terminal melted (jumper cables are fine). After that he agreed to connect negative to grounded metal inside the chassis. The car started and I let it run for a few minutes. Immediately after removing the cables the car died.

He decided to try connecting straight to battery again. No sparks or anything but my car did not react at all when I tried to start it.

The battery is only a few months old. Do I now need to replace it? Is it possible that we damaged something?

The blind leading the blind…When the sparks flew and the terminal melted, the connection was backwards, Positive to Negative and a big mistake. From here, it’s impossible to tell how extensive the damage is…Time to be towed to a repair shop that can handle auto-electrical problems…Hopefully it’s just some burned wires and fuse-able links…

If it was reversed wouldn’t sparks fly from everywhere? They only flew from one terminal.
I figured the sparks ignited the gases that the battery vents and the resulting heat melted the terminal

Agree with Caddy. Prolly need a new battery that has failed and a new alternator and maybe a new computer.

My first thought was what Caddyman said. Even though you didn’t say it in your opening post, I too strongly suspect the connection was backwards.

Hopefully your damage is limited to the battery and a fuseable link. I’ve seen cases where that’s all that went bad. One mark of that was after the cables were connected properly, the engine ran while the cables were connected, but stalled as soon as the cables were removed.

If any electronics got fried, it will be more costly, both for the time to figure out what got fried as well as the cost of replacement components.

ggsimmonds wrote:
I figured the sparks ignited the gases that the battery vents and the resulting heat melted the terminal

You’d need a lot of gas burning for a long time to melt a heavy piece of metal. That’s not what happened here. This was a high electrical current due to reversing the polarity or somehow creating a short-circuit. As mentioned above, your best bet is towing the car to a shop that can check out all the electrical components that might have been damaged here.

If you’re unlucky, this could be an expensive repair. Possibly you should ask your apartment complex to help pay for it, as maybe it would fall under their insurance. However, if this guy was doing you a favor and wasn’t supposed to do this, he could end up getting in big trouble as a result, so that’s a consideration before asking.

So…Im confused… what is now the issue? Aside from when whomever decided to hook up the jump cables incorrectly. Just as Caddy said…there is no telling what damage has been inflicted with the incorrect cable hookup…Ive seen nothing happen…and Ive seen catastrophic computer and wire loom damage occur. The vehicle has large High Amp fuses in place to try and protect for these instances but even that doesnt stop things from happening.

If you now have no batt power at all…I would at least first n foremost put a voltmeter on the battery…see what kind of voltage you have… This will tell you what you need to know about battery health at least part of the way. If you DO have voltage…then you need to check the large high amp fuses to see what youve got…whats blown and whats not.

We are still at square one with this one… We need to know batt voltage and if any large fuses have popped.


Funny story from my past (and it is relevant). I once owned an MG1100, which had a positive ground battery.

I once had it jump started accidentally with the polarity backwards. The car started, the generator worked, the radio worked, it had become a negative ground car. For a bit, as the battery was being discharged by the generator instead of charged. I had to replace the battery and re-polarize the generator. I should have just turned the battery around and left it as a negative ground vehicle.


I would suspect some fusible links have been blown.

One reason I would be hesitant about bringing apartment management into this is because the guy could lose his job.
Poor technique aside, he was trying to be a Good Samaritan and I’d hate to see the guy (who may have a family depending on him) get axed over this.

Yeah I don’t want to get the guy in trouble, he is a good guy and we chat a lot.

Towing service is on the way. I hope the damage is not severe, the car starting should be a good sign right?

Sucks because I just replaced the battery in February.

Thanks guys

Hey you might be fine… Replace the battery…and see what you got…

The first step after getting your vehicle operating is to join AAA or some other auto club and let professionals jump your vehicle.

The first step after getting your vehicle operating is to join AAA or some other auto club and let professionals jump your vehicle.

A BETTER alternative to an auto club is getting a rider on your insurance that covers this. I have it on all our vehicles. I think it costs me $15/yr. Since there is only ONE AAA gas station within 20 miles of my house I can choose ANY garage to come over and jump my battery…instead of waiting HOURS for the one garage to free up.

Negative to negative is the way we jump started vehicles for many years. It’s no longer the proper way to jump start a car but it won’t cause jumper cables to melt. Connecting the cables backward will. In a case like this…you just have to fix the easiest thing first and continue on. If you are lucky it may just be a fusible link or a fuse but it’s most likely a fried computer. Good luck.

Figured I would update you guys. The good news, like I thought he did not actually reverse the connections. What he did do, and I did not notice, was allow the cables to snake around each other. That has much the same effect.

Just installed a new battery and post but as I feared, electronics are gone. Will have to take the car back friday after I get paid.

Hoping it is just a fuse, but it could be worse.

I’d think that a short-circuit wouldn’t hurt the electronics the way that reverse polarity would. Let’s hope now it’s just a fusible link or something along those lines.

“the cables to snake around each other” would not cause the damage, in fact, would be just fine. Only reverse polarity would do that.

You can get sparks without reverse polarity.

If the battery had a shorted cell that may explain how things happened here, that is assuming that the jumper connections were made correctly in the beginning.

As mentioned above, connecting the two battery negatives directly (after connecting the positives directly) is discouraged b/c of a safety issue involving sparks near the battery, not an electrical system damage issue. Snaking the cables is not a problem either, unless a non-insulated surface touches something it shouldn’t, which apparently is what happened. In most cases that would be a simple short circuit and the damage should be localized to where the short occurred. In this case, the battery.

Since you’ve replaced the battery and the car remains inoperable, getting a pro involved makes sense. It could still be something fairly simple. Suggest you visit a well-recommended inde mechanic rather than a chain store that sells batteries for this.

As I suspect you realize, unlike cars of the past, newer cars don’t take well to jump starting. Suggest you discontinue this practice. When the battery is dead, ask someone to help you remove the battery and take it to a shop where they’ll recharge and test it. In the meantime, take the bus. Or a cab. You’ll be money ahead.