Hey everyone, this is my first post to this forum. I recently had the first ever issue with my 2002 LS430, a failed alternator. My car sat in my shop for 2 months while I did a mini restore on it... paint correction, refinished factory wheels etc... On the first day driving it to work. the battery light came on and almost left me stranded on the side of the road. I bought a Denso 210-0508 Re-manufactured alternator and a brand new battery just for good measure and installed them over the weekend.
I took the car out for a test drive and everything seemed great, no battery light and the car seemed normal. When I got home and pulled the car into the garage I smelled an electrical smell and a small amount of smoke was coming from the area of the alternator. I thought maybe this was just oil they used to keep the bearings and brushes from rusting. Concerned about being stuck on the way to work, I got back into the car and took it for another 5 mile test drive close to the house. When I got back, no smell and no smoke.

I got into the car this morning to go to work and the battery light is back on!

My question is, I'm assuming the regulator is built into this alternator? Is it possible that I got a bad alternator? There isn't enough voltage coming into the alternator to fry it, correct? The cables can only go on one way and everything is clean and extremely well maintained on my car. What am I missing here?

 

Maybe put a tester to the battery terminals and test both the battery and alternator? I think it is altogether possible to have a faulty replacement part. With my Maxima, I had to put in 3 starter motors, and all 3 were AC Delco "new," not remanufactured. First two were faulty and even though lifetime warranty, I wasted shipping and my labor....(AC Delco has since removed the lifetime warranty, now that is funny, after the fact)

 

After thinking about this situation for a few hours I have developed a theory. I just realized that both alternator failures have something in common, a weak battery. The first alternator failed mid-way between the house and work (a span of 30 minutes) after the car had sat for 2 months. I made it to work and bought a new battery over lunch so that I could get the car home. I drove an hour home that afternoon on the new battery (failed alternator) but failed to put the battery on a charger when I got home. I then drove the car with the new alternator and new battery for about the same time on a test drive and it failed.

What do you think the possibility of both alternators running at full capacity for 20 minutes attempting to charge an almost dead battery, then frying the regulator would be? I am thinking that since the LS430 is so dependent on electrical for everything, this may be what happened?

 

It's possible. An alternator isn't designed to charge a dead battery, just maintain a good one. I would check your battery cables very closely for internal corrosion. It usually shows up as a white powder where the terminal is crimped on but can extend quite a ways internally down the cable. Corroded cables are very stiff and not flexible. If you have a volt meter I would check the voltage at the battery with the car off and with it running. The voltage regulator is the most common failure point on these alternators followed by worn brushes. All remanufactured alternators use crappy Chinese regulators so 2 failures in a row is not unheard of.