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Ls400 Electrical Problems


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I own a 95 LS400 (bought from family friend) with $97k, have had it for 2.5 years and 40k miles, nothing other than tires/oil/brake service before I bought it. Since then, new ball joints, new control arms, new auto antenna.

However, I have had the following problems haunt me:

Problem 1: A year ago - A wiring harness in the trunk has experienced some corrosion, obviously b/c of moisture in the trunk and a missing piece of rubber. The wiring harnesses were related to the phone control module. The initial problem was a muted radio and a fan blower that didn't work (a high tech feature of the phone - when it receives incoming calls, the fan and radio are automatically turned to low during the call). Dealership A spent two weeks on the car for diagnosis and the solution they came up with was to by-pass the phone control unit.........lot of troubleshooting, new parts tried, old parts replaced, etc........no significant charge ($150) b/c they didn't fix anything. I asked them to properly remove the phone unit yet they didn't convey confidence and said let's see if it works this way. Within a month I started to notice that the only speaker with consistent output was the front drivers side. The others would come and go about 5% of the time. Took back to Dealer A and they said I needed a new amp - $900 Nakamichi amp. I went to local guru who put in a functional Nakamichi amp (from salvage yard, and how he determined functional, I don't know, but the same symptoms presented itself so I almost have to believe him) and speaker output problem wasn't resolved, so we put originial amp back in and assumed it was not the problem. I then went to local audio sound installer and they determined all the speakers were perfectly fine. That leaves me to believe it's back to the amp or it's a wiring problem. I think it's the latter. A Lexus Owners Club member thought that it was still related to the phone control unit, and that the front left speaker is the output for the hands-free conversation and the other three speakers are muted. Sounds like he's onto something. Didn't want to call Dealer A back b/c I wasn't convinced they were competent in handling this, so I called Dealer B to handle and they said they could - but I wasn't in any hurry.

Problem 2: Last month - I came backed to my parked car and noticed the drivers side window was down. I started driving home and noticed locks were "self-locking", yet this stopped when I locked the doors from the inside. My wife took the car to the store and said the window rolled down when she unlocked the doors using the keyless entry. Sometimes it did, sometimes it didn't. I know a feature of the car is that the windows will go down if you unlock the drivers door and hold the key to the right, but this is kinda strange. I called Dealer B to make an appointment for this problem and problem above, with the current problem more important from a personal security standpoint. Dealer B quickly showed their incompetency as well. Maybe I'm foolish for assuming the Lexus dealers should know what they are doing - but I do, and that's why I pay them a premium over another mechanic. Anyway, Dealer B replace two parts in my door, one which they diagnosed as the problem and the other which happened to break (these things happen, the car is 10 years old, I understand). They only charged me the labor on the first part, and the total was $513. I went to pick the car up and they tried to give me my car back without any functionality in the instrument panel and the driver's door console was literally hanging. I left upset b/c of the inconvenience and the fact that I already paid them. I picked up my car again the next day and everything looked good. On the car ride home the locks started acting up, and that night the window opened on it's own again. The next morning the locks were acting up some much and were so loud that I thought someone was throwing snowballs at my garage door. Frustrated, I took it back and that's where I stand. It's been another week, and my service rep has been out sick so I think the car has been sitting. I'm not too upset b/c the loaner car does it's job. I understand they have another part on order, which is interesting b/c nobody contacted me for approval to fix anything.

That's my situation. Please provide any insight if you can. I want to believe the two maybe related in some how, yet not sure. I find that the Owners Club is better at troubleshooting problems and offering up suggestion than my two local dealers.

I'm all about getting this fixed, yet I'm not one to throw money away. I haven't dealt with the $520 that I already paid, but I tend to think the dealer should refund the entire amount, place my original part back in the door, keep the new part that they broke (due to mis-diagnosis), and eat the labor cost. I don't know if this sounds unreasonable, so please comment.

Thanks for listening, and I look forward to hearing from you. :unsure:

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Hello. The bad news is that electrical systems on these newer advanced cars can be very complex. I really do not have any idea what could be your problem with the door lock and windows, but it sounds like an electrical short somewhere. I think it is unusual, since Toyotas & Lexus' typically rate the highest in electrical system reliability. Actually- most all Japanese makes rate high in electrical system reliability- particulary Hondas-Acuras and Nissans-Infinitis. I have been reading a lot of electrical problems here lately on the LS400s- especially on the 93-97 models. The 90-92s for some reason seem to not have as many problems. I consider myself lucky that my 1990 LS400, with 226,000 has a perfect electrical system, with everything working perfectly- except for 1/2 of my climate control buttons do not illuminate when the lights are on- which is a very common problem on these cars- at least the 90-94 models.

I noticed you are saying "Dealer A and B". Is there a third dealer that you can take it to? Also, the fact that they have a part "on order" and you have not authorized any repairs sounds peculiar to me.

The part about the wiring harness in your trunk is a common problem I think. I have not had the problem (yet anyway), but I have heard that other members have had this problem, but it was causing other bizarre things with the electrical system. I guess different wiring can be chafed and therefore the different problems.

Sorry I could not be of more help. Perhaps someone here will have more answers.

Good luck to you.

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