1998 Ls400 All Gauge Needles Failing After 10 Minutes

[Leadfoot]

Bought a 98 a few weeks ago and it was behaving well, until last week when the Fuel, Speedometer, Rev and temp needles all started malfunctioning.

I have a good battery and put new terminals onto the leads to grip the battery posts firmly, as they were a little loose. Car is fine in all other respects. No malfunction light is showing, no errors listed in the readout display, which also keeps working when the needles fail. Ambient temp = 72F (22C)

Problem = They always work correctly after the vehicle has been turned off for a while. Drive for 10-12 minutes and they will suddenly either drop to no reading, or even stranger they move to half deflection. Stop for a while then they work again.

I have done a search but can't find anything similar. Any clues?

[1990LS400]

Attached are the only two TSIBs I could find regarding combination meter malfunctions on 1998 U.S. spec LS400s.

The 25 pages about the combination meter in my 00 LS400 repair manual do not discuss how to resolve specific problems - only gives voltage and continuety specifications.

Fluctuation_of_combination_meter.pdf

Miles_since_refuel.pdf

[VMF]

it does sound like an electrical problem to me. might be a bad chip or a bad capacitor that messes things up when it gets worm. not sure bout your model year but there are companies here in US that can fix 90-94 clusters if you send it to them.

[Leadfoot]

Thanks for the response Jim, very informative. I didn't know about the shipping pin. Appreciate the time you spent searching.

VMF, I agree, it seems to be electronic. The charging system holds a steady 13.7 volts regardless of RPM (2000-5000). Rang the local Lexus Dealer and they have a company they send the combination meter assembly to for checking. I will update this thread after they holiday season is over and I have gotten a result.

Thanks again.

[Leadfoot]

Well my wife got the car back today, the instrument cluster had been removed and sent to a specialist who found a few faulty capacitors and replaced them, drove it away from the repair shop for 10 minutes and tada! no gauge readings. AAARRRRRGGGGGHHHHHHHH! I hate it when simple stuff goes wrong, its so frustrating. So back to the shop for another go at it. I took some photos of the boards on the back of the cluster so will pull it apart again if they get it going and see which ones they replaced. I am glad I am 12K miles away or I would vent my frustration in a nonhelpful way!

[Leadfoot]

Well, time for an update. After 6 weeks in the specialists lab they couldn't make the cluster reliable and have given up. They say even though it works intermittenly the easiest thing to do is fit a replacement. Replacement cluster panel PCB and gauges is USD 6,353 from my local Lexus Dealer. That is not a typo, its half as much as I paid for the whole CAR!!! Tried to find a replacement through the breakers, but guess what! nobody is wrecking a 1998 in the whole country (NZ). Not good so far.

So took the car and sick cluster to a recommend "whizkid" who has performed some miracles on merc clusters. After 1 week he phoned up to inform me he has now totally fried my board, so now nothing works at all. I drove it home today with a gapping hole in front of me. A distinct low point in my Lexus ownership history.

So I need to source part number 83800-50070 - an "Australasian" spec cluster. Looks like its going to be a long time before she is back on the road......

[Leadfoot]

Time for an update. After being unable to source a RHD cluster anywhere in the asia-pacific area I bought an instrument cluster from a wrecked 2000 LS400 in the UK. I carried the damn thing home to NZ in my hand luggage. Not one customs or security person asked me what it was.

So the good news, I now have a euro spec cluster working perfectly in an australasian spec car, no problems. Only took me 5 months to get fixed..........

Sure is nice to be back on the road.

[SKperformance]

lol , glad to hear, i know us wreckers have a few for a few hundred.

I am surprised it did not make a bunch of warning light issues after replacing it since you drove it with no cluster.

[jcrome04]

It's about time! lol

[90LS400Lexus]

Good to hear you got it fixed... I would have been totally disgusted and given up!

My 1991 LS has 210K and still has a perfectly working cluster, but I wonder for how long. <_< I know its only a matter of time before either the dash lighting or gauges go on the fritz. :(

[eatingupblacktop]

Good to hear you got it fixed... I would have been totally disgusted and given up!

My 1991 LS has 210K and still has a perfectly working cluster, but I wonder for how long. <_< I know its only a matter of time before either the dash lighting or gauges go on the fritz. :(

If I'm not mistaken, I think cluster issues are more of a 2nd gen problem.

[SKperformance]

Their is one tsb for ucf20 's but the 1st gen cluster has issues of capacitors burning over time and gauges failing.