2coupetim

I own a 2000 ls400 the alternator got fried by power steering leak (lol). i replaced fuse and put in a new 100amp alt and now when i go to hook up my battery it instantly blows the alt fuse. ive gone back under and tried finding the problem only thing i found was that the pigtail plugged into the back of the alt had a little bit of white corrosion on the part that goes into the port. would this be my problem??? do i replace just the pigtail or whole harness??? also at some point everything on my interior quit working. i changed the “dome” fuse and still nothing im at a total loss i want to cry and im musty any knowledge helps

Yamae

I suspect that the rectifier diodes are short-circuited. I'd be checking the resistance between the terminal B and the body of the alternator. If it's close to 0 ohm, you probably will need to replace the rectifier or simply install a new or rebuilt good alternator.

Another thing I worry about is that you are not telling us everything you have done since the problem is not only the blown 120A alternator fuse. Didn't you try an incorrect jump starting?

2coupetim

I did have to jump it, and it made it drive long enough to get into my driveway. I made sure clamps on both ends were correct. turned the car off after i got into the driveway thats when it all quit working it was before i even tried to do the alternator job where the interior functions quit working they worked fine when jumped but now the only thing that works is door chime and door light but yes i made sure battery was disconnected when i went to do the job i made sure all connections were clean and plugged in the correct pattern even while jumping the car. power steering has been leaking on it for a while and i think the wiring is messed up wondering if anybody else has had a problem like this since p/s is a big problem with ls400s i suspect the pigtail plugged into the back of the alt is the problem the clip that locks it into place broke off but it still plugs into the port but on the old alt there was white corrosion on the inside of the pigtail port the harness had a very brittle casing on it and crumbled when i went to unplug the old alt it will start with battery connected but will die bc the alt isnt able to charge the battery and since the interior functions dont work its stuck in park car drove perfect before this problem never had any problems except this

Yamae

Did you use a jump cable with a surge protector?
https://www.mynrma.com.au/roadside-a...ot-a-good-idea
https://firstbatterycentre.co.za/why...-a-modern-car/
https://www.automotiveforums.com/t98..._vehicles.html

Other than the reversed connection, what I mean to say "incorrect jump starting" is to use a plain jump cable which doesn't have a surge voltage protector. Without it, the surge may damage your car.

Regarding the fix of the car, I'd replace the alternator using only a Denso's alternator. I never use any others.

I suspect that the surge voltage damaged the body computer. So I'd also check the inside of the body computer to investigate why changing the “dome” fuse doesn't help. This needs to use an oscilloscope and a logic analyzer. I'm quite used to use those but those who are not may try to use a good working a body computer.