Mechanics

TOYOTA COROLLA FUSE PROBLEM

2000 Toyota Corolla • 200,000 miles

Accidentally reversed the battery cables when I hooked them up. Not only that buy I also didnt realize it until after I had tried to start the car. I noticed I had some blown fuses the main one being the 100amp altenator fuse. I replaced it and got power to the car but the car does not turnover nor does it even make an attempt to. There are a few fuses I still need to replace. Is it possible I fried all relays in the car? I am looking for any suggestions on what steps to take on fixing my problem. Thanks.
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Guest
February 27, 2013.



You didn't hurt any relays. There are a lot of computers on your car and they all have diodes to protect them from reverse polarity. A diode is a one-way valve for electricity. They are installed backward and don't normally do anything. When you connect the battery backward, those diodes become a dead short which forces the fuse to blow to protect the rest of the circuit. You can't expect things to work until all the blown fuses are replaced. Chances are everything will work then.

For future reference, the positive battery post is larger in diameter than the negative one. The cable clamps are also different sizes.

Caradiodoc
Feb 28, 2013.