what happens when you hook up car battery cables wrong?

left my lights on.took battery out to charge and put battery backwards.while the battery was dead the lights on the dash turned on after it was tryed to be hooked up backwards now with a full battery it doesnt want to start.also the lights on the dash dont even turn on

10 Answers

  • ?
    Lv 6
    7 years ago
    Best Answer

    If your lucky you blow many fuses. But alot of the times every electrical component will puff magic smoke and will need replacing. Especially the Computer, Radio and Body Control Module

  • yanez
    Lv 4
    3 years ago

    Hook Up A Car Battery

  • 7 years ago

    Hooking up the battery backwards causes a surge that blows the engine main fuse, which is why you're not getting squat in the instrument cluster or otherwise. The main fuse is usually found in the engine bay's fuse box.

    If you're really in a jam, u can open the fuse and using a thin enough wire, recreate the link between the two points in the fuse until u can replace it. But turn the battery the correct way first, before u do this. :)

  • mahlon
    Lv 6
    7 years ago

    If you're lucky and you not only hook them up to the wrong terminals, but you don't make a good connection, then maybe nothing will happen, maybe a few sparks. If you're NOT so lucky, the sparks can ignite the fumes from the battery and cause an explosion. And anticipating other answers that might dispute that simply out of ignorance, don't listen to them.

    Here's a simple guide: hook up one of the red connections on the jumper cables to the red terminal on the dead battery; then hook up the other red connection on the jumper cables to the red terminal on the good battery; then connect the black end of the jumper cables to the black end of the good battery; last, hook up the black connection of the jumper cable to a piece of the car's metal frame (not to the black terminal of the dead battery). The farther away from the dead battery, the better.

    Source(s): I saw a battery explode once and that was enough for me.
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  • 7 years ago

    The previous owner did that to my Dodge Caravan

    - blew out the Body Control Module

    - screwed up all the instrument lights

    - affected the heater dispersal doors and actuators.

  • 3 years ago

    What happen if you put the battery post on wrong on the negative side. Whining sound and woke up the next morning the battery in ruin and the sun won't start.

  • 3 years ago


  • Anonymous
    7 years ago

    Car battery lead terminals--are different sizes..?

    • Mark5 years agoReport

      Yes finally someone said it - I was beginning to wonder. Unless of coarse you are talking about a side post battery.

  • John
    Lv 6
    7 years ago



  • 5 years ago


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