rome99LS

Intresting to know that guys, ill def keep an eye out on the altenator that I just put in and ill check its voltage to make sure its 13.9v or so. I know the altenator is average is high 13s volts. Thanks.

lonnie247

How is the alternator now (13.9v)? Just searched for a problem I started having and found this handy and timely thread. Looks like I'll also need to find a new alternator soon.

rome99LS

Its still good..no problems...I got mine from Advance Auto parts w/ a Lifetime Warranty!. So im def good.

Wats urs doing to make u think u need one?

lonnie247

Switched out a bad battery Friday. Saturday I got the Headlight Leveler warning then a battery light and later a Check VSC warning. Just enough power to get it to the shop.

wbc0522

I had the similar problem 2 weeks ago.

1. While driving in the late afternoon, the battery light was flashing and a few second later the headlight leveling warning was displayed on as well. Several minutes later, the battery light became off and the headlight leveling was still remaining on. Restarted the engine everything became normal.
2. While driving in the same day at night, battery light was suddenly on and immediately the headlight leveling warning was displayed. This time both message remained on. after 15 minutes a lot of warning lights were on (break, ..., etc.). 5 minutes after all warning lights were on, the interior light became darker and darker, and then after another 10 minutes, I lost all electricity power including headlight (engine was still running). Parked my car in a nearby parking lot, and the car cannot restart.
3. The second day, roadside assistance came to help and was told the battery was dead. After installing a new battery, the engine can be restarted. However, the alternator test was not stable (sometimes pass and sometimes fail).
4. On the way to the Lexus dealer, when the speed was around 75 mph, the battery light was off. When my car was slow down, the battery light was on again. (This repeats several times)
5. Bring the car to the Lexus dealer for inspection, and was told the alternator was charging. Bring the old battery to Sam's club for testing, and was told the battery was dead. Ha... It's battery problem! But the story is not end ...
6. Same day at night, the battery light is on and the headlight leveling message was displayed.
7. Next day, bring the car to the Lexus dealer again for inspection, and was told the alternator needs to be replaced for $700+.
8. Having a new alternator installed and no problem for 1 week.
9. Again, the battery light is on again and the headlight leveling warning is displayed.

I plan to bring the car to the Lexus dealer again tomorrow morning.

JJDAG

So what was the outcome after the last trip to the dealer that replaced your alternator? I have the same symptoms but very intermittent, the battery light comes on with the headlight leveling warning light, the first time if i revved the engine the battery light would go off, I parked the car and took my truck when I came back to check the car all lights were off and car ran fine for several weeks, then the same thing happened only this time I was on the highway for a good 20 miles before I got the car home again i switched into my truck and later that day checked the car and it was fine battery voltage 12.9 car off 13.7 running at idle. third time the battery light came on at start up I shut the car off and restarted light still on I tested the voltage at the battery while at idle this time 12.8 , so i started to drive home and the light just went off in a very short distance, I ran a couple errand then brought car home still no light on.

JJDAG

I forgot to mention I replaced the alternator and battery last fall I used a Delco alternator as they advertised they replaced all the bushings regulator where the Denso said they just check , I had no problems with it until know.

LS9698

Sorry about your alternator.
Just to point out the obvious.
NEW batteries still need to be fully charged up before put into service,.
I use a trickle charger on them for 24 hours to give them a good charge to start off their life in service.
I've had less than perfect alternator's go out right after putting in new batteries in my youth.
Just my .02 cents.

LS9698

Wow, I read this thread 2 weeks ago and the exact same thing just happened to my 98 LS.

Headlight Leveling and battery indicator came on and had to get towed home.

I charged the battery to 12.5 v. Restarted the engine and meter reads 12.1 v. at idle, pulled the alt. fuse and still 12.1 v. So nothing is coming from the alternator.

Personally I believe the regulators on these might be what's causing failure, but they cost about $95.00 to $120. +.
So I will replace the whole thing.

I just replaced the radiator and hoses myself 6 weeks ago. It might make doing the alt. easier by taking out the radiator. (Again).

Yamae

I have seen many non Denso alternators last only several months. Those fail in summer time a lot. Denso's regulator has a special circuit inside which works to limit the current inrush. Denso has a patent about this and it's called "Jorei-Hatsuden" in Japanese. The purpose of this is not to stress the alternator and the engine. Non Denso regulators don't have this circuit and I find them fail rather quickly. Also Denso's alternator can generate enough current even at the idling. I recommend people to use a Denso's one.
https://www.clublexus.com/forums/ls-...-96-ls400.html

JJDAG

Thanks Yamae! I appreciate your help
John