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

Eletrical system issues

Thread Tools
 
Search this Thread
 
Old Sep 18, 2014 | 02:51 PM
  #1  
1uzae86's Avatar
1uzae86
Thread Starter
Driver School Candidate
 
Joined: Mar 2010
Posts: 26
Likes: 0
From: Or
Question Eletrical system issues

Ok so I have a very annoying electrical issue that has arisen in the last couple weeks and seems to slowly be getting worse.

Symptoms:
-Factory Nakamichi stereo cuts out randomly with occasional loss of power (witnessed by power antenna retracting)
-headlights and any lights on dim
-parking indicator lights dim and brightness pulsates if turn signals are on or I pump the brakes
NEW symptoms:
occasionally when rolling windows up/down or opening/shutting sunroof and the action finishes stereo now occasionally cuts out or audio level diminishes significantly.
a couple days ago I did find what appeared to be a ground wire for the remote trunk opener that was broken, patched it up but symptoms are still persisting.

I had my alternator tested earlier today (9/18/14) both with the hand held tester thingy and old school method (pulling + terminal off), after the electronic test was done and the results printed out something caught my eye and the person who did the test, on the result paper it said "ripple detected" does anyone know what that means?
Battery was bought 2-3 hours before I got the car (5/714), alternator was picked up and installed the next day (5/8/14)


At this rate I'm cutting my losses, I'm good with wiring but I don't have the time to put the car down for inspection of the electrical system and possibly dash harness visual inspection
Reply
Old Sep 18, 2014 | 05:14 PM
  #2  
Yamae's Avatar
Yamae
CL Community Team
10 Year Member
Liked
Loved
Top Answer: 1
 
Joined: Aug 2011
Posts: 4,172
Likes: 1,006
From: Japan
Default

Originally Posted by 1uzae86
I had my alternator tested earlier today (9/18/14) both with the hand held tester thingy and old school method (pulling + terminal off), after the electronic test was done and the results printed out something caught my eye and the person who did the test, on the result paper it said "ripple detected" does anyone know what that means?
Battery was bought 2-3 hours before I got the car (5/714), alternator was picked up and installed the next day (5/8/14)
The link below shows the waveforms of an alternator and the yellow lines are the ripple part.
http://jaguar.professional.org/Alternator.php

I worry that your alternator has some problem rectifying the 3 phases AC. Probably rectifying diodes are not fully working properly and the ripple is bigger. If so, you will have undercharging problems as you mention.
Reply
Old Sep 19, 2014 | 07:23 AM
  #3  
fixmiester's Avatar
fixmiester
Intermediate
10 Year Member
 
Joined: Jan 2012
Posts: 306
Likes: 33
From: TX
Default Nice article on alternators

[QUOTE=Yamae;8717919]The link below shows the waveforms of an alternator and the yellow lines are the ripple part.
http://jaguar.professional.org/Alternator.php

I worry that your alternator has some problem rectifying the 3 phases AC. Probably rectifying diodes are not fully working properly and the ripple is bigger. If so, you will have undercharging problems as you mention.[/QUOTE

That's a nice link to basic alternator operation and useful checks with a scope or DVM. The waveform pictures do a good job of explaining 3 phase rectifiers, but he did make a mistake in the last picture showing a "shorted diode" ; in that case the yellow waveform (composite voltage) would have a negative excursion going below the zero volt reference. His last picture is instead identical to the previous one showing an open diode. But he did a good job otherwise. Thanks for sharing.
Reply
Old Sep 20, 2014 | 05:34 PM
  #4  
simrx3's Avatar
simrx3
Driver
 
Joined: Dec 2012
Posts: 123
Likes: 0
From: AUS, nsw
Default

check battery connections..

ie remove clean the clamp and post with a wire brush and reconnect..

also do this to the body earth connection from the battery and the engine block earth..

this should solve your problem
Reply
Old Sep 24, 2014 | 06:56 PM
  #5  
1uzae86's Avatar
1uzae86
Thread Starter
Driver School Candidate
 
Joined: Mar 2010
Posts: 26
Likes: 0
From: Or
Default

Fortunately I didn't need to do any terminal and earth connection cleaning, I had the alternator put on a test bench and the Diode came back bad. Got it replaced and so far the issues are no longer present, I believe when I put power steering fluid in the pump to try and locate the leak the PO told me about, it leaked enough to cause the diode and possibly other internal issues.

But sadly due to my financial situation I can longer afford to keep my 91 LS400 and have been offered a 2001 Honda Civic 5spd and cash, I am taking the offer because I need fuel economy for how much city driving I do looking for work. I will be back to the Lexus scene when my financial situation allows me to do so. Thank you guys for your help since I purchased my LS400 back in May, I have learned quite a bit and still have learning to do!
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
bezeeduzit
SC - 1st Gen (1992-2000)
5
Apr 13, 2010 09:47 AM
mr. aristo
Lexus Audio, Video, Security & Electronics
7
Jan 27, 2006 07:21 PM
bezeeduzit
Maintenance
3
Nov 3, 2004 01:33 PM
bezeeduzit
Lexus Audio, Video, Security & Electronics
10
Aug 10, 2004 06:22 AM
TXLeXTC
Lexus Audio, Video, Security & Electronics
2
Sep 11, 2002 03:27 AM




All times are GMT -7. The time now is 04:16 AM.

story-0
10 Lexus Designs That Have Aged Like Fine Wine

Slideshow: Some luxury cars chase trends, but these Lexus models look better now than they did when they first rolled into showrooms.

By Verdad Gallardo | 2026-05-06 17:58:29


VIEW MORE
story-1
8 Tips for Improving Your Hybrid or Plug-in Hybrid's Efficiency!

Slideshow: How to Get the Best Fuel Economy with a Hybrid and Plug-In Hybrid!

By Michael S. Palmer | 2026-05-05 20:54:44


VIEW MORE
story-2
10 Best Lexus Models No One Remembers

Slideshow: 10 best Lexus models no one remembers.

By Joe Kucinski | 2026-05-05 17:33:28


VIEW MORE
story-3
TRD Off-Road Premium: Best 2026 4Runner, Except This One Thing

Slideshow: diving into 4Runner TRD Off-Road Premium's pricing, performance, fuel economy, features, and amenities!

By Michael S. Palmer | 2026-04-23 13:09:18


VIEW MORE
story-4
Top 10 Lexus & Toyotas to Drive Before You Die!

Slideshow: the 10 Lexus and Toyota vehicles you need to drive before you die.

By Joe Kucinski | 2026-04-23 10:34:24


VIEW MORE
story-5
Top 10 Lexus/Toyotas With The LEAST 5-Year Depreciation

Slideshow: Top 10 Lexus/Toyota models with the lowest 5-year depreciation rate.

By Joe Kucinski | 2026-04-08 12:19:06


VIEW MORE
story-6
Lexus LC500 Convertible Auction: A Preview of Rising Values?

The LC hasn't even disappeared from the Lexus lineup yet, and we're already seeing signs of an explosive market.

By Brett Foote | 2026-04-06 09:25:02


VIEW MORE
story-7
GX 550 vs TX 550: Best 3-Row Luxury Lexus Family Hauler

Slideshow: comparing the pricings, specs, power, fuel economy, fun-factor, and features of the GX 550 Luxury+ and TX 550h+ Luxury.

By Michael S. Palmer | 2026-03-19 13:44:11


VIEW MORE
story-8
9 Best Lexus Models You Can Buy for Half Price (And 1 You Shouldn't!)

Slideshow: 9 best Lexus models you can buy for half price and 1 you should avoid

By Joe Kucinski | 2026-03-19 12:01:07


VIEW MORE
story-9
2026 Lexus NX Buyer's Guide: Models, Features, Prices & More!

Here's everything you need to know about the latest NX.

By Brett Foote | 2026-03-19 11:56:59


VIEW MORE