trukn1

Alternator fuse is brand spanking new this year. I replaced that earlier this year since,in the process of elimination, I discovered the one I had was probably the original and was starting to deteriorate.

fonzo

This is one of the best books I have read. You will figure it out you guys are the best

Lazy

iTrader: (2)

Hmmm changed plenty of alternators for lots of different cars n I rebuild them as well.. Ur alt is charging from testing it by removing the battery terminal n it stayed on.. Check ur wires again. Here r some of the problems I had doing it on a few cars.. Short in the wires somewhere, fuse, powersteering fluid leaking into alternator or could be any liquid going in it can mess it up.. Regulators r all the same ****.. Any brand can be defective from factory.. We just recently did my cousins GS400 alt because the car was dying from the alt being bad n battery would drain fast then we replaced it n the lights came back on but the car didn't die n he drove it like 40 miles or so n it still didn't die on him but the lights stayed on. Then we tested it and it was over charging so we rebuilt the same one n it was fine. I changed my 92 LS400 alt about 2-3 times because of the lights too.. First was the powersteering leaked into it.. Then there was a short from the alt wire.. Autozone tested one of our alt before we put it in n it failed but when I tested it on our own machine it passed n it worked when it was installed so it could be a bad alt too..

Lazy

iTrader: (2)

Looks like u did everything u could haha.. I would try another alt n if the lights stay on then it's time to do some digging around all ur wires.. Sub wires or if u have an aftermarket head unit it can drain ur battery as well if not installed properly.. If u did anything to the car before the lights came on then double check it

tomtheslac

Most of the dash components go thru the AM1 fuse next to the alternator. If you don't mind driving with no radio, window, speedo, doorlocks, heat, tilt steering, younameit...you can pull the fuse and see if you still get a drain. You pretty much get only headlights and brakelights, and nothing else. If you suspect something in the dash, I would first try this. Pulling the dash is a major job, and some terminals get really brittle after 20 years. Just guessing, but I would think someone did some creative wiring with an aftermarket headunit...low enough draw not to cause smoke.

Good luck

jabyrd3

I've been having this exact problem for the past 3 weeks on a 91 ls 400! I lurked here for a bit, decided to get my alt tested, had it repaired at a local alt shop, and put it back in on sunday. Last night the gremlins came back, my lights dimmed a TON when I was idling, and this morning my car wouldn't start.

I honestly joined up to make a new topic about this. When I got my alt/battery tested at autozone the guy said the batt looked fine. Whats the simplest diag I could run for this? I'm pretty sure I have an old voltmeter kicking around my apt somewhere.

randal

See post #11 and associated link.

trukn1

Lazy,,, pretty much thinking along the same lines here. Know there is no power steering fluid leaking into the alt. Had that completely repaired @Lexus last year (rack, pump, reserviou, lines) to a pretty hefty tune. Headunit in car is still the factory, only bypassed the amp so I could get the aftermarket amp and subs working. This has been the setup for the past 4 years runnig now, and no new audio work has been done. Had pretty good results with Denso alternators in the past (was replaced due to PS leak back in the day). Now running some other brand and I may just try to switch back as the particular brand may just not be cutting it.

Tom,,,,Pulled the dash last weekend while I was home and took that apart. Is actually still sitting on my bedroom floor where I left it, to check to see if maybe the dash had gone up pn me. Circuit borad looks good, no leaks at any of the capacitors, and no burnt areas. Am not a comp geek, but do have some elementary knowledge of what I am looking at here. My dash came out in about 20 minutes without incident, and no clips were broken in the process. Gonna inspect the wiring behing the cluster before re-assembling this weekend.

Fonzo,,, lol,, you got jokes. Just make sure you are at my apt. ready to do work son!!!

jerryparks

iTrader: (1)

I have read all the posts here to see if my problem matches. My alternator
was removed and tested by both autozone and a professional repair shop that has a high end testing machine that checks the diodes and regulator.
It checks out OK @ 14.5 volts. I get 11.75 volts at the battery after reinstall. Both my
connection terminals are new. I also cleaned the multi wire plug in at the alternator and removed any junk with a small brush.

Am I reading the posts right that you can add a new negative wire at the
battery and run it to the alternator, and just no longer use the old neg wire?
Where does it connect at the alternator? I see only one heavy duty
wire that connects to the alternator?

Do I need to check any fuses and where are they? Thanks

trukn1

I installed a new multipost bettery terminal at the battery and ran a new negative (ground wire) to a new ground point on the car itself, not the alternator.

jerryparks

iTrader: (1)

Fixed charging problem! Re-installed the alternator and made sure the plug was in good. Also added a new main ground wire from the battery to the frame. I'm now getting over 14 volts. Thank the Lord! This is no weather
to work on a car outside.

trukn1

Figured since hardly anyone ever updates their own thread, I would do so.

Finally think I have the problem solved(once again). After running out of things to look for and check,, just went back to basics and started over again. Got it narrowed down to, indeed, the alternator. Yanked that POS, rebuilt(yeah right) alternator off my car, grabbed one from the boneyard from an SC400 (LS400 are pretty scarce in my area and those found have the PS leak) and installed. Gave the battery a good charge (cold weather has really put a beating on them, especially since I havent been moving the car), and took her for a spin. Everything seemed like it was back to normal, headlights stayed nice and bright (have developed my own visual headlight meter,,LOL!!) and no more warning lamps. YAY!!!! Drove her around for about 2 hours and seems that all is well again. Still need to put a volt meter on her to see what she is reading, but with the "field test" no problems showed up, as they did before within the same time period. Now just gotta reset the ECU to get the airbag light to go off now. Thanks for all of the inputs and suggestions.

deanshark

First, thanks for updating your own post. Like ya said, not too many do. (I'm guilty myself ) Hopefully it stays working for you. As for the airbag light, http://www.lexls.com/tutorials/light...rbaglight.html Not sure if you knew about that b/c you said you had to reset the ECU.

python

iTrader: (4)

thx for the update bro. congrats on the fix!

trukn1

Was exactly what I was referring to when i made the statement. Just hadn't gotten around to doing so yet.

Python--Thanks bruh!!