Jump start reverse polarity..

[mika44 Lurker Find all posts View Profile Close mika44]

Ive recently tried to jumpstart my prado in without paying enough attention to the correct polarity...
2000 turbo diesel 1kzte.

Now when the engine is running the alternator wont charge, air filter restriction light is on, hand brake light is on, oil level light is on.

Ive found the 100amp fuse blown so i replaced. Pulled the alternator apart and changed the regulator as that was blown, but alternator still wont charge. Ive checked every fuse under the dash and in the engine bay

Anyone have a wiring diagram or can anyone help, thanks

[Matty80 Avid PP Poster! Find all posts View Profile Close Matty80]

Check your fuses, its likely that the dead short between the two batteries blew one of them...

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Fuses:

ALT
ALT-S
GUAGE
IG1 No2

You have also most likely blown some diode in the alternator.

Cheers
Leigh

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

Hi Leigh, do you think it would've blown a diode? I thought the only reason you blew the diodes was when the battery load went open or very high resistance. In which case the alternator AC voltage could spike up over 100V and typically the diodes are only rated for about 80V. Given the purpose of a diode, the reverse polarity I wouldn't think would affect them. But then again, I'm not autoelec! But am certainly curious.

[adrian5800 Advanced Member Find all posts View Profile Close adrian5800]

When you reverse polarity you send a shitload of current through the diodes in the alternator and that's what fries them. Put simply in normal operation they stop current from the battery going to earth and allow current from the stator out to charge the battery etc.

Ades

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

Yeah fair point. I didn't consider the several kA pumped through them. Lol

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

If your vehicle has a 100A etc fuse to protect the alternator you maybe be lucky and it
blew before the diodes, if the alternator is not now charging then it will be either the
diodes or the regulator.

Cheers
Leigh