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LS 400/LS 430 Electrical Questions & Problems



  • wwestwwest Posts: 10,706
    There is for certain an amp under the front passenger seat but I seem to remember another one, bass speaker driver(??), in the trunk.
  • j7wildj7wild Posts: 14
    yes it's in the trunk, you will need to pull the trunk carpeting off... did you see my link above?
  • darinhdarinh Posts: 1
    Hi Damien15,

    Mine was located in the trunk, drivers side, just left of the gas tank. Of course I had already found the site " carstereohelp" and pulled my CD changer out before I realized that mine wasn't under there. Still a good site and will go there for info. again.
  • I Have a 1992 Lexus ls 400 with @ 270,000 Kilometers on it.. The engine occasionally shuts down if I use anything electric on it ... For example, If I touch the brake peddle, use the turn signal, open / close the window, the car will stall out and usually restart immediately. It doesn't happen al the time, just occasionally but I cannot find any common factor. Also, whether it is related or not, the gear shift lever will jam and the release button has to be hit hard to release it.. If the car shuts down, the lever must be jiggled to get the car to restart. Other than the electrics problems its a great little car and runs fine.. any suggestions ... thanks...
  • if you go back to my previous post #19 on page 2 , my problem was caused by the alternator starting to short out so I had it and the battery replaced.

    Everything ran fine for about a month and then I started having a problem SIMILAR to yours and to #10 on page 2.

    Same thing: car will jerk like it's downshifting when I apply the brakes and the Reverse indicator on the dash will come on and the whole instrument panel will fade out.

    Also if I turn the headlights on and I'm going faster than 30mph, the speedometer will drop to 30mph and it won't go any faster and the engine rev meter will go up to 4 or 5 and it sounds like you are driving in neutral.

    The first time this happened I was driving home from a friend's house at 3 am , 16 miles away, and I pretty much limped home at 25 mph max.

    One more thing is the O/D indicator will flash saying it's off and then it disappear.

    I took it back for repair and they replaced a cable in the taillight that was shorting out and it caused a brake light to go out.

    After that, it's working fine now and I hope it stays that way.
  • I own a 1993 LS400. I had a similar problem but not as crazy, found that there is a cluster of wires in the trunk hinge on the drivers side. Constant wear from opening and closing the trunk one of the wires had been cut. Everytime I applied the brakes the reverse light on the panel would lite up and the car would "clunk" as if it was trying to go into reverse. Don't know if this will help but there are alot of wires in that cluster something could be cut and causing your car to go haywire!
  • yeah I'm gonna check it out because there light out warning light on my instrument panel keep lighting up and I had my wife stand behind the car while I use the turn signals, the hazard, step on the brake, turn the lights on and she can't see a single light that's out

    thanks vguthrie
  • acco20acco20 Posts: 208
    I will soon need a new battery for my 2001 LS430. I have checked the battery itself and I have checked all the manuals and can not find any numbers or discriptions that would lead me to buy the right battery. I mean what size, cranking power etc. I am concerned when I do not know exactly what I am looking for. Can anyone help??? Thank you. wwest...are you out there by any chance...
  • wwestwwest Posts: 10,706
    I have been buying my replacement batteries at Costco of late and simply rely on their cross-reference catalog.
  • j7wildj7wild Posts: 14
    for my 1992 LS 400 was a 430 cranking amp battery and that's because the guy at Auto Zone told me I needed something that big for such big car
  • wwestwwest Posts: 10,706
    The biggest "challenge" for your car battery is in cranking the engine. These days most starter motors are reduction geared and therefore require less cranking amps than in days gone by. Additionally with all the electronics in control, especially EFI, engines simply start a LOT quicker.

    I would wager that a small garden tractor battery would supply enough AMPS to start an LSes V8 but accordingly would not have a very long life.
  • j7wildj7wild Posts: 14
    Wwest, so the guy at Auto Zone conned me then?

  • wwestwwest Posts: 10,706
    No, just good salesmanship...

    Except for lightening your wallet slightly more than necessary he did you no harm.

    Manufacturers of late have become a bit more conscious of weight vs MPG issues so while the higher capacity battery will undoubtedly weight more than the OEM it will also likely last longer.
  • wwestwwest Posts: 10,706
    The CD player in my brother's 91 LS400 will not change discs nor open the CD door but will play the CD currently in position. I traced the problem down to a pico fuse in the "head" unit. Does anyone know of a shop that specializes in Lexus radio repair...??
  • j7wildj7wild Posts: 14
    that's the Toshiba 6 disc changer in the trunk?

    same I have on my 1992 LS 400?

    same happen to mine, wouldn't open or change disc and I even try the reset on the remote control on the dash

    took it to Lexus, they couldn't fix it

    took it to a car stereo place, they told me don't bother

    so it's still in the trunk, just doesn't work anymore
  • I don't think it pays to fix these old things anymore. I'd just replace it.
  • j7wildj7wild Posts: 14
    you are correct; I feel the same way.

    but I wouldn't even spent the money on a new car stereo for a 16 year old Lexus with 200,000 miles on it

    my nephew is turning 16 next year and is going to start to drive - I am thinking how selling the car to him - his first car, a Lexus!!

    my first car was a 1976 beat up old dodge van with no ac and am stereo
  • wwestwwest Posts: 10,706
    1991-92 LS400 radio often blows one of the fusible links inside the radio head. Specifically the one that passes the B+ from the dome fuse through the radio and then out to the CD. C21 pin 4 from the dome fuse into the radio and then through the fusible link to C9 pin 6 out to the CD. There is a second fusible link for the acc B+ out to the CD but that one doesn't blow.

    Anyone have experience with this...??

    Radio aways operates even with the fusible link blown and CD works perfectly until the fusible link blows, days or weeks apart.
  • wwestwwest Posts: 10,706
    I am in the process of wiring in an external fuse in parallel with the internal pico fuse. Shall I copy you on instructions...??
  • wwestwwest Posts: 10,706
    B+ (battery 12 VDC) pin at the CD player connector was shorted to ground. Provided a B+ power bypass around the connector and all is well.
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