fjohnson98

I bought a 98 ls two weeks ago and it has been a constant project. I thought I got it for a decent price but, I've been dumping money like crazy (guess I should have inspected it a bit more carefully). I have installed crossdrilled slotted rotors all the way around, ceramic brakes, kyb struts and mounts, all 4 sway bar links, front sway bar bushing, both upper control arms, left outer tie rod, new tires (yoko envigor) and I still have to replace the lower ball joints. I'm having a few issues now and I've searched here and google to no avail. My first problem is that both power seats are not working at all. I'm sure it's a fuse/relay/control module thing, but I don't know what fuses/relays to check and since there's no adjustments for the seats, I can't slide the seats forward or backward to get to the bolts in order to take a look at the seat computer. The second issue I'm having is that when I accelerate from a stop there's a slight shudder around 1500 rpm and it only happens when coming from a stop. Could this be a transmission related issue or possibly the coils? The next issue I have is with the sunroof--it will open and slide back properly, but when I try to tilt it up, it will move maybe a half inch then stop. After that, hitting tilt up or down does absolutely nothing. The only way I can make the sunroof close is by using opening the sunroof completely and then closing it with the slide button. This is an excellent car and with the work that I've put into it and intend to in the future, I'd like to keep it around for a while. Oh and by the way, this is an excellent site as it has already helped me troubleshoot a few other minor issues I've had recently...in fact i'm going to replace the lower ball joints myself (trying to reduce the labor costs).

jgabem

Dont know if this will help the seats, but I remember a while ago, I bought a 91 LS400 and the seats didnt work, the previous owner was a monster and my mechanic could not figure out the electrical issue, so I drove around with a huge pillow behind me. Needless to say, I was ready to drop some money at the electrical auto shop when I stumbled upon a website I dont remeber which one, but all they recommended I do was grab a toothpick and reset some button, its right by the fuse box underneath the drivers fuse box and its got a little hole at the bottom, insert the toothpick and push up see if it has it and it works, did for me, seats were dead and for me low and behold every single button on them started working.

Check this out, has info on this issue, looks like the part you have to poke is called a circuit breaker...

http://us.lexusownersclub.com/forums...howtopic=26021

fjohnson98

Thanks for the suggestion, but I checked near the fuse panel and I saw no such thing. Must not exist on the 98-00's but there might be something similar that I missed.

qewani1

Download this file - body electrical part of 98-00 LS400
http://www.sendspace.com/file/l0dczl

fjohnson98

Thanks for the link, I will find it to be VERY useful once I'm able to get to the control unit for the seats. Problem still is being able to move the seats without any power so I can get to the 4 bolts that hold the seat in place. I think I can solve the sunroof problem using the repair manual fairly easily, so the manual will definitely come in handy for that. The only other major concern I have is the shuddering when coming from a stop at 1500 rpm. Anyone able to chime in on this?

JimsGX

Need more details on the shudder... Is it coming from the front, center or rear of the vehicle? Do you feel it through the seat, through the accelerator pedal or through the steering wheel? Is it dependent on speed or just RPM? Will it do it in neutral, drive? Sitting still or only when the car is moving? If when moving only, does it do it within a certain speed range even when coasting in neutral? Or just RPM range regardless of speed?

Close the sunroof and forget about it for now...

fjohnson98

The sunroof opens and closes just fine, it's just the tilt not working, but I really am not too concerned with that right now. As far as the shudder goes, it doesn't happen in neutral or park and it's ONLY when moving from a parked/stopped position. I had an old galant that did the same exact thing except it was a bit more pronounced than in the LS. It ended up being a bad ignition coil. The shudder always occurs around 1500-1700 rpm no matter how hard or soft I accelerate, and you can feel it a bit in the steering wheel but mostly in the accelerator.

fjohnson98

Any help on these issues, especially the seats, before I break out the blowtorch and cutting tools?

qewani1

For seats problem have a look here
http://translate.googleusercontent.c...A5TVajCfQybSPA

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http://translate.googleusercontent.c...vgDK2z6UC3jSUw
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http://translate.googleusercontent.c...sO82IOeZ-gpgjg
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http://translate.googleusercontent.c...FQ64dDTggXPNOw
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http://translate.googleusercontent.c..._0OJPKaq252iAA
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http://translate.googleusercontent.c...gVd8vax1WUMlnA

These are for front seats.

fjohnson98

Thanks for the link, but unfortunately without being able to move the seats, I can't get to the 4 bolts that secure them down. I'm trying to find a deal on replacement front seats so I can take the sawzall and cutting torch to them.

Kansas

There are detailed diagnostic procedures for almost every electrical circuit in the repair manuals for your car or at https://techinfo.toyota.com

A Sawzall (my Dewalt is my favorite tool!) is a bit severe. The cause of your power seat issue could be pretty simple and have nothing to do with the seats themselves. If you don't want to buy the repair manuals, you can do a $15 2-day subscription to techinfo and download the information you need.

Sometimes an experienced Lexus trained technician is worth the money. Diagnosing issues like this seems easy for my Lexus mechanic Fred but he's been working on Lexus cars since day one.