newmannoah1

So just bought a 99 ls400, drove an hour home no issues, after about 2 hours sitting at the house went to go get food and wouldnt start. jumped if started fine but while cables were connected battery light was still on, disconnect the negative jumper cable and light went away, but anytime out back on it would come back. replaced battery yesterday and battery light is now on without jumper cables on it. would think alternator but wondering if could be anything else snd if if alternators are a common problem?

Yamae

Sorry for your trouble. Sounds like the alternator is dead. It is an often case that leaked power steering oil damages the alternator's brushes and the alternator stops the generation. I'd check the generating voltage as well as the leaking power steering oil. If the alternator is wet with power steering oil, you will need to repair both.

GoldStar

^^What he said. If you do swap out the alternator, consider an upgrade to the higher-amperage LS430 alternator, just need stud 90109-08298 and nut 90080-17242. You can find Denso-remanufactered alternators on RockAuto. For more info, see: https://www.clublexus.com/forums/ls-...ml#post9838495

newmannoah1

thank you for the help, also i was gonna ask anyway it could like a blown alternator fuse or anything? and what part on the power steering usually ends of leaking and killing the alternator?

newmannoah1

Sounds good i appreciate the help

timmy0tool

iTrader: (7)

it's a small $3 o-ring at the bottom of the PS reservoir that fails. the reservoir sits on the top of the PS pump, and when it leaks it drips down to the alternator directly below. very common issue!

from an older LS400 but it's similar to your 99.

newmannoah1

appreciate the help a lot, any chance u have part number?

400fanboy

If I recall correctly, broken motor mounts allowing the engine to move move than it should would put extra stress on the hose leading from the reservoir as well and that could also be a failure point. I think this is worst on 98+ but I'm not sure.

https://www.amayama.com/en/catalogs/...20-1997-r-3473

I find my part numbers using this interface. It has all the diagrams and it can visually map the part number you're looking for.