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Consequences of Hooking a Car Battery backwards

I recently took my 1995 Ford Escort wagon (150,000 miles) to a well known chain to have the battery replaced.

When they put installed the battery, they hooked it up backwards and blew the main fuse. When the main fuse was replaced and I was driving off I noticed that the charging light was on, and the radio/clock was not working. Taking it back, they confirmed that the alternator was dead and replaced it (with me paying for it). The radio still does not work and the tailgate light is blinking on-and-off.

I understand that attaching the battery incorrectly may blow the alternator, it seems way too much of a coincidence. I also understand that it may have affected the car’s computers.

What recourse do I have with the company and more importantly what other possible damage could there be?

Do you have proof that they attached the cables backwards? Not that I doubt it having happened, it is just that you will need to show someone that it was their fault. I guess it is fair to say they owe you the money for the alternator and also fixing everything else on the car. Why did you need a new battery anyways? Was the alternator fine before they worked on it?

Yes, I do have proof, they told me that they did and I was there waiting for the vehicle. It wouldn’t start after the battery was out in and an experienced mechanic came to check it and diagnosed the problem. They said that the old battery was put in backwards (physically) and when they replaced it, they just hooked the cables back up (and I am presuming they never checked how the old battery was hooked up) but to the wrong terminals. It sounds like it was careless work not checking the cables/terminals correctly when disconnecting the old battery.

The old battery was tested by my regular mechanic and came up as “bad” with 48% charge. It had been parked with the lights on for 30 minutes and had to be jumped afterwards. It was probably about 5 years old. The alternator light had never come on before.

I also noticed this afternoon that it wasn’t starting smoothly but cranking a while before hand. I’m now beginning to wonder if other systems were affected such as the starter and the onboard computer which may not give the right mixture. The blinking rear door dash light could well be a faulty sensor caused by the incorrect wiring. Reading around on other sights it seems the clock/radio could be out because of “fried” wires.

In future discussions about this situation don’t say “they put my battery in backwards” just say they "hooked my battery up backwards’ I say this because I really had to sift through a few sentances in your post that really did not have to be there.

Get your story down real clear and don’t “gusssie it up” with things like “an experienced mechanic came over” just say they hooked my battery up backwards and they admit it. If I was in a position to make a decision about your claim I would want to just hear the cold facts.

I jumped a battery backwards once(I was real young) it sounded like a .45 went off, blew the tops off the battery and split the case, very dangerous.

Thanks for the feedback. The old battery was put in backwards but hooked up correctly. The new battery was put in correctly but hooked up incorrectly. Hope that’s clearer.

As of this moment I am also concerned about other after-effects which could affect my car as it’s my primary means of transport. I was wondering if something else could go wrong with it.

No, that’s not clearer. In fact, I’m confused. In small claims court, just say, “They ADMITTED to hooking up my battery INCORRECTLY.” If you aren’t clear, and concise, in your claim, you might lose your claim.

You need to go to the shop manager or store manager for resolution. You should not have to pay for any parts or labor for the new alternator. Hooking up the battery incorrectly blew the alternator. As to other problems, radio etc., you need to get the manager to agree that these were affected as well. The store should pay to restore your car to the condition is was in before they messed up the battery installation.

The position of the old battery is not material, and is no excuse for the store hooking up the + cable to the - terminal of the battery. They owe you to make it right, it was their mistake.

Reversing the battery connections is not too uncommon. If the key is off the damage is often just fusible links and fuses and the alternator. If, however, the key is on a great deal of damage can be done. Many relays, the computer, the ignitin switch, etc. If the starter was engaged, it too might have been damaged. And there is the possibility that wires, anyhwere in the harnesses, have damaged insulation but won’t short out until some future time. The McParts stores that install batteries have all paid dearly on occasion for their efforts at “free” customer service. And one of the big box stores here once sold a generic battery with the polarity marked incorrectly. They were selling and installing group 24 batteries with 24R labels and lids. It was particulary costly on a couple of cars.

First, let me say, I cannot believe they had the gall to ask you to pay for the alternator. Its demise was a direct result of their negligence. Regardless of how the old battery was installed, it is their responsibility to insure that the correct cables are attached to the correct posts on the replacement battery. They goof, they pay.

There are “wires” in the engine bay that are designed to open up in an over-current situation. They are called fusible links. The car also has fuses on all of the electrical circuits to protect the wiring from burning up in the event of an over-current situation. So, the polarity reversal may have resulted in one or more fusible links and/or fuses blowing to protect the wiring. The wires themselves do not care about polarity so the likelyhood of any additional wiring harness wires being “fried” is remote.

What can happen is that any electrical device on the power bus may have been compromised. For example, your radio is likely to not only have a fuse on the general circuit feeding it and other compoenents, but also an internal fuse to protect the wires feeding just the radio. Sometimes, they do not even have fuses internally but some electrical component on the power supply front end is sacrificed so the radio becomes inoperative. If your radio is dead, it needs to be repaired or replaced (assuming the general circuit fuse is OK).

With regard to the longer cranking times, it’s probably a result of the battery power being removed from the ECM and so it lost all of the memory stores for operating parameters. It has to re-learn over time and use to custom tailor the controls to the engine condition. The older the engine, the more likely it requires some custom settings to operate best since it no longer matches the performance of a new engine. If the ECM is doing its job, it’s probably fine and in time, it will adjust to the settings necessary to operate as it did prior to the battery swap.

The rest of the electrical problems should be fixed on their dime with nothing but yes sir, yes sir, three bags full. Your problems are the direct result of their negligence and you deserve full compensation. I wouldn’t settle for anything less.

Hooking up a battery backwards will definitely fry a car radio, I know from past experience…it also ruined a CB radio. :frowning:

Your post was completely clear and you explained the situation in a way that any grade-schooler could understand it.

Sounds right to me the more I think about it. The guy who put in the new battery failed to check the polarity of the cables when removing the old battery. I shall follow up with the manager and if that doesn’t work, then all the way up the chain.

Thanks! That was the idea.

Like Twinturbo, I’m appalled that they made you pay for the new alternator. They’re clearly responsible for having damaged the original, as well as the radio. They probably also fried a wire for the tailgate light causing an intermittant short to ground that’s completing the circuit intermittantly.

Make sure everything is documented and keep your copies of the shop orders. Write a clear letter to the franchise manager and/or owner outlining the problem and requesting a full refund on the battery as well as repair of the associated damages. Attach copies of the “evidence”. Give him a chance to make good. I know if I were the owner I’d get everything back in order free of charge as well as refund you the cost of the battery. The reputation of my shop would be far more valuable than what the cost would be. He may just feel the same way.

Post back with your results.