2003 Toyota Landcruiser Reverse polarity on jumpstart attempt

JOSEPHDOTO

MEMBER
2003 TOYOTA LANDCRUISER
4.7L
V8
4WD
AUTOMATIC
110,000 MILES

I was attempting to jumpstart a 2003 Toyota Landcruiser and because of poor lighting had a reverse polarity situation. The headlights came on so that I did not immediately recognize that I had reversed the polarity. After correcting the polarity situation some of the dashboard lights come on but the starting circuit is not energized. I looked at the underhood fuse box and circuit breakers, I do not see any blown fuses or burnt wires. Is there a main circuit breaker or fuse that I should check or test?

1 Reply

CARADIODOC

MECHANIC
33,727 POSTS

There should also be a fuse box inside.

While it's possible some computers were damaged, they usually have diodes built in that become a short circuit when the polarity is reversed. That forces its fuse to blow which saves that computer.

Also look for fuse link wires. Most vehicles have gone to large cartridge fuses now, but if there are any wires, they'll be a short piece that's a different color, and is spliced into the main wire. You test them by tugging on them. If they act like a wire, they're okay. If they act like a rubber band, they're burned open. The advantage of a fuse link wire is it takes some time for them to burn open. They don't pop as quickly as a regular fuse.