LS - 1st and 2nd Gen (1990-2000) Discussion topics related to the 1990 - 2000 Lexus LS400

Battery or Alternator or?

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Old 02-25-13, 06:15 PM
  #16  
Yamae
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It sounds like a cracked regulator IC problem in the alternator to me.

Below is what I heard from a company owner who runs an alternator rebuilding company. He said," Many after market regulators are not as good as Denso's and do not last long. He found most of those tend to have cracked IC problems and show intermittent charging problem in a few years.

He added," Denso has many special test equipments for the heat cycle and the heat shock tests and they design and make parts to pass all those strict tests. But after market ones may be not and I find many cracked regulators among them since a regulator is heat cycled every time a car runs."

I know many Celsior owners in Japan to have too low voltage problems within a few years after they have replaced the alternator. Those are all after market ones.

The owner also said, "We only use Denso's regulator to re-build the alternator not to have complains from customers but Denso's regulator alone costs more than $100 and I must say it's a bit too expensive."
Old 02-26-13, 01:14 AM
  #17  
LScowboyLS
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I rebuilt my original Denso alternator, with a couple of special tools it is really easy - I knew the regulator was much better heat-sinked, than the aftermarket alternators

an alternative would be to get your alternator from a place like advance auto parts, who has a very small core charge ($22) and then you can just keep your original Denso alternator and steal the regulator from it and put it on the replacement alternator!
Old 02-26-13, 08:18 PM
  #18  
SUPRAboy80
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Originally Posted by Kansas
Sounds very famillar from my 13 1/2 years with a 1990 LS400. Is the power steering pump leaking fluid on to the alternator?
yes mine is... can you help me?
Old 02-27-13, 10:04 AM
  #19  
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Deffo sounds like an alternator to me. I wish I would have rebuilt mine instead of replacing it. Was factory denso but now its an aftermarket one.
Old 02-27-13, 11:17 AM
  #20  
j2b4o
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I think I bought my OEM denso for like $100 or so. Found it more difficult to find all the parts for a full rebuild.
Old 02-27-13, 06:48 PM
  #21  
LScowboyLS
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I think I bought my OEM denso for like $100 or so.
Not for a new one you didn't, and I have never heard of a reman for that price level either!
Old 02-28-13, 09:34 AM
  #22  
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Check battery terminal maybe that's just bad, happened to me
Old 03-04-13, 06:41 AM
  #23  
crcuevas
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Well I took it to a indy shop and they couldn't find anything (which I don't believe). I still get the dim lights when applying brakes. I also replaced the connector on the alternator. I may just replace the alternator and get a Denso and never buy a Autozone anymore
Old 03-04-13, 06:59 AM
  #24  
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Turn the ac, headlamps, stereo, and ws wipers on. Then check voltage at battery. If below 13v replace alternator. The system will not work right with less than 13v.
Old 03-04-13, 09:37 AM
  #25  
j2b4o
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Originally Posted by LScowboyLS
Not for a new one you didn't, and I have never heard of a reman for that price level either!
Check rockauto next time
110$
40$ core
Denso OEM
I have a 90' so it may be more for the newer models.
Old 03-06-13, 01:00 AM
  #26  
whit3b0y
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I went through 3 alts in 1month. Check your power steering system. check the hoses that go from the pump to resivior and vise verse. Even if they drip a little and you cant tell, its still enough to kill your alt. Remember liquide and electrical dont mix. I replaced mine and then put spark plug heat sleaves around the hoses, to prevent future decay of those hoses. I would bet this is the issue.

check the harnes, I have had the charge wire in a harnes rust through, your alt could be putting out the right amount but the battery might not be recieving it. but it sounds like it is recieveing a charge since its dropping.
Old 03-20-13, 01:27 AM
  #27  
lsd4hunnit
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Had the same problem last Friday night, I was leaving work and when I hopped on the freeway my radio and headlights kept turning off and back on, it was foggy too! Turned out to be poor connections from the battery
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