Instrument cluster clock/climate control

[zen999]

hello guys, it is good to be back again. i recently joined the club. I have bought a 91 lexus with a power steering problem( stiff) I recently had it check, the p/s fluid level is full with dextron 111 (red fluid). i friend of mine drove it around and says might be the rack and pinion unit. p/s pump has been replaced. but any way will still probably do a little more t/shooting. anyway i also have the same problem with lcd display. it appears to be blacked out. but here is the catch.. i live in arizona so the temp is up to 110degrees while cleaning the interior one time. i found out the lcd is not blacked out anymore at a reading of 84.5 dgrees. here is the question. will this be a fuse related? thnks for advice..

[hlovepenn]

I have had a '91 LS400 for eight years and 218,00 miles and have had most of the problems possible. I had the clock-temp replaced for about $325 at my Lexus mechanics in Plano. However, there are quite a few units available, rebuilt, on Ebay. To replace, you can find instructions at most audio repair internet sites for removal instructions. As for other parts, Lexus shares a lot of parts with regular Toyota parts. Find an internet site, look up a part for the Lexus and then either type into browser search or go to a discount Toyota site and put in the part number. E.g., for lamps for the LS400 run about $35.00 at the dealer. They also fit the Supra, I believe, and run about $19.00 at a Toyota dealer. AJUSA has K&N airfilters right now for $47.00 shipping incld. That's two Lexus filters. My power steering has leaked for a while, but it has finally stopped and I saved $1200 on the unit. I just bought a '96 LS400 and am having to replace a few of the usual items--hood struts, front struts, etc. By the way, I have replaced my plugs with Walmart platinum Champions and they have worked great! Let me know if you have any questions.

[wolver1ne516]

Yeah, My 91 LS 400's doing it too...And there is someone who does sell just the screen and it's easy to do with a little TLC.

Go to Ebay and search for Lexus parts follow your search from there and you should find another lexus club member there not only carring info for the part, but instructions for the job, as well as charging about $250 to do the job for ya. (not too shabby).

wolverine516 B)

[jadecuir]

Does anyone know where to get a good used or rebuilt clock/climate control for 92' LS 400? The LCD display turning black seems to be a very common problem. I have checked with many auto-wreckers, they either don't have any left or are in the same condition (turning black). I had heard there were some retired Air Force personnel in California that rebuilt them.

PS: Given the number of problems, one might think that Lexus would step in and do a recall or sell rebuilt units,  $800+ for a new one is a bit steep.      thanks,  bob

←

Search on ebay for "Lexus climate control". There are two competing sellers who sell "kits" for replacing thr LCD and bulbs. One is "buy it now" for $160 + shipping, and it usually bids right up to that price. The other seller starts bidding at $20.00, and it always (so far)bids up to $140.00 or so (+ shipping). For an extra $15.00 shipping, you can send in the unit whole, and he will do the soldering and bulb replacement for you, no charge. They are both in CA, and have links or will email instructions on R & R and soldering. It's pretty easy to R & R the unit, but the soldering is the tricky part. For the extra $15.00 dollars, it's worth it to let them do it.

John

[jadecuir]

the site listed above doesnt have the instruction on how to get the trim up....

←

The tabs are on the rear of the shift plate. Pry up the aft corners with a taped (so you don't scratch anything) screwdriver until the clips are free, lift the aft end no more than one inch, then pull aft until forward end comes free of slots. Put in nuetral, turn and lift over shifter knob. The ashtray unit pulls straight out. Use screwdriver to pry the upper corners out a little, then pull aft, with ashtray closed.

Remove wire-plugs. Upper vent removes same as ashtray. Unplug.

Four screws hold the Radio/climate control unit in. A magnetic screwdriver is a good idea here. If you drop a screw here, it's probably gone.

Pull the whole unit aft and unplug the climate control unit. Remember that the radio has anti-theft code, and if it's never been reset (like after dead battery or something) and you unplug it, you may have to have the dealer reset.

There are two screws on each side that hold the CCDU to the radio side brackets. Take those out, then pry the brackets outward a little and the unit is free!

John

[RFeldes]

Has anybody tried painting the needle backs with "conductive" paint?

[dcfish]

Has anybody tried painting the needle backs with "conductive" paint?

←

If you paint the needles they WILL need to be rebalanced DEFINETLY....There is a small brass plate on the back of each needly that you can pry off with a small knife or similar object and there are weights inside the needle base you will have to add weight to the base some times a couple of drops of elmers glue will do the trick [ elmers glue can be removed with ease if the balance needs to be adjusted ] The needles just pull off . The balance on the needles is extremley sensitive. When replacing the needles push them on firmly but not too far towards the guage plate [ they can be adjusted about a quarter of a turn ] so make sure when you replace them the gas is FULL , The engine is at running temp , and the speedo reads 0 and the tach is just at o , Take readings of your entire cluster before you take this project on , For example if your temp is just below the 1/2 way mark when warmed up, That is the way you want it after rebalancing. I have been through the entire process of disassembling and reassembling a 92 - 96 es cluster.

[michaelsn]

dcfish,

Can you recommend a specfic "conductive" paint for this project?

On a related topic, since you have the expertise in working with the instrument cluster, would you be able to determine what causes the tachmeter and the speedometer to work intermittently?

Thanks,

Michael

[dcfish]

dcfish,

Can you recommend a specfic "conductive" paint for this project?

On a related topic, since you have the expertise in working with the instrument cluster, would you be able to determine what causes the tachmeter and the speedometer to work intermittently?

Thanks,

Michael

←

A CONDUCTIVE PAINT IS NOT THE ANSWER.....The painting of the needle will not repair the CONDUCTIVITY it will make the needle off balance, once the original needle fails it will have to be reworked , If you buy new from the dealer or from personal sale they WILL FAIL sooner or later , The best way is to have them LED'D at www.lextech.org or you can mess up your dash any way that seems fit to you............................................................................................................. B)

[RFeldes]

Always one for a challenge, I will inspect the needle with a magnifier and see if there is a break in the conductivity and "lightly" spray with conductive paint and give it a go. If it works fine!! I'll post it..If it fails...then.. I will order a new one.

worth a try.

[dcfish]

Always one for a challenge, I will inspect the needle with a magnifier and see if there is a break in the conductivity and "lightly" spray with conductive paint and give it a go. If it works fine!! I'll post it..If it fails...then.. I will order a new one.

worth a try.

←

By the way , With the intermitent lighting of the needles is caused by the very first of many to come tiny cracks in the factory elements , They will soon become more and more brittle then fail , All of the needles WILL fail in time , The best option is to have them reworked with LED'S.

[RFeldes]

DCFish...I believe you may be correct..but I find myself a little bit concerned by your adament replies...maybe as if you are connected to the LCD company..We at LOC will decide through our own initiatives what will save us money for other things such as PS pumps and the like. Let me, an engineer, decide if there is an alternative to the needle problem and you give it a rest and wish me luck for the rest of us with 15 year old 400's. The short fuse may be behind you. Give it a rest!

[dcfish]

DCFish...I believe you may be correct..but I find myself a little bit concerned by your adament replies...maybe as if you are connected to the LCD company..We at LOC will decide through our own initiatives what will save us money for other things such as PS pumps and the like. Let me, an engineer, decide if there is an alternative to the needle problem and you give it a rest and wish me luck for the rest of us with 15 year old 400's. The short fuse may be behind you. Give it a rest!

←

WOOOOHHH!!! I did not intend to hit a nerve , Just trying to help. HAPPY HOLIDAYS!!!!!

[92Lex]

hey dcfish, my cluster is perfect but have you tried the needle kit from lextech? I came across that site a few months back and kept in in my favorites just incase.

[dcfish]

hey dcfish, my cluster is perfect but have you tried the needle kit from lextech? I came across that site a few months back and kept in in my favorites just incase.

←

LEXTECH.ORG Is where I finally had my 93es300 cluster done and I am quite happy with the results :D I also replaced every backlight for $19.99 and the cluster looks and works like new.

[92Lex]

Sounds good. I plan on changing my backlights with the bright white ones they have. I probally wont be changing it anytime soon though, I don't want to get myself into it until it's needed. Thanks for the info.

[dcfish]

Sounds good. I plan on changing my backlights with the bright white ones they have. I probally wont be changing it anytime soon though, I don't want to get myself into it until it's needed. Thanks for the info.

←

Here's some info on your needles and what is happening. First, this is what you would see if you could freeze the flickering in a dead standstill:

http://www.lextech.org/images/needlesandna...edlecloseon.jpg

The reason for this is here:

http://www.lextech.org/images/needlesandna...eheatdamage.jpg

Heat damage. non repairable, non reversible. BUT replaceable

Now, first let me say that if there are any questions from this post feel free to email me at sales@lextech.org, however I am going to try and be very specific so "everyone" reading can benefit.

You ask why your needles don't give you as much trouble with the headlights on. Try this experiment here:

go outside and turn your dimmer switch just off of the high position click (full on) down with your headlights off. Didnt make a hill of beans difference did it? NOW keep it in that position and turn the headlights on.

They dimmed! That's because the headlight circut will activate the second stage in the dimmer module when on and cut exactly .5 volt from the cluster. This is JUST ENOUGH to give the led's a slight break from "full voltage". That dimmer module is not just a knob, inside are a few chips and some diodes that regulate two lines to the cluster. one of them is full on (no headlights) one is controlled on (headlights on) which no matter what you do will always keep the cluster at .5 volt lower than the other way.

Why? Lexus didn't actually plan on this to happen (actually nippendenso since they make the unit). It is simple electronic theory, more easily said "it's the way it is" . See, whan you add a diode inline it drops the voltage of the line exactly .5 to .6 volt. This is one of the characteristics of the diode in an electronic circut. It just happens that you can see this little quirk of electronic technology since the needles that are sufficiently damaged are leaning on the brink of self destruction if that little tiny amount of energy is applied and helps finish overheating them.

You guy's wanna know the truth? That .5 volt extra is exactly what does the needles in...Nippendenso designed the clusters to run off of the dimmer module and never took into account what would happen if the headlights were off and bypassed the dimmer section #2 where the module kicks the diode in that saves the extra .5 volt. That's why they work fine with the headlights on.

In short......... Design flaw.

Why do the needles flicker?

-- They "dance" and flicker under the concept of the "flasher module" relay. If anyone has ever seen how a flasher module works, a small thin piece of aluminum is layed against a hot post when the post is "hot" it heats the piece of metal up and it bends away from the pole for about 1 second (just enough time to cool down and return). After the cool down, the metal returns to the pole and the process is repeated. It heats back up, pulls away from the pole and cools back down and returns. What you see..... is flashing! the contact touches, pulls away, then cools down and touches again. WHOLA! you have a flasher relay.

You also have a flasher needle too As the needle heats up it expands the contacts and they pull away. when they cool down about .4 tenths of a second later they come back, touch again, and bounce back off from expansion by the heat.

You basically have a flasher relay going on not by your choice. What this looks like, is a "dance" in the needle.

This should clear things up and if you need to ask anything else please feel free to email, I will be happy to help. It helps to get answers from an Engineer rather than a Technician. Techs just open units and replace parts, don't know why they failed, don't care, can't prevent it in the future.

Fortunately LLS is made of engineers and every concept is a fully engineered redesign to prevent future problems.

[92Lex]

My entire cluster is working just fine...no flickering needle or anything of that nature. I just wanted brighter backlighting.

[Lexls]

Guys, the LS needles are NOT LED's like the GS and ES, they're cold cathodes!!! I've talked to Lextech.org and he doesn't have a solution for the LS. In fact, he doesn't want to work on LS units at all because of the cold cathodes. I don't think you can just install the LED needles Lextech sells, there's different circuitry. I have never heard of anyone swaping cathodes for LED's. The LS cluster is an entirely different animal....

The LS cold cathode needles do have some sort of conductive material on the back of them. I know because I've tested it and the black material completes a circuit; it actually has a small resistance B).

[92Lex]

Yeah, but the backlighting (numbers) aren't.

[Lexls]

Backlighting on the LS is also cold cathode, for the speedo and tach. The rest uses just regular bulbs. I know the backlighting on the SC, which is what Lextech does a lot of, is a number of bulbs.

[92Lex]

Really? Which ones are you refering to when you say "the rest"?

[Lexls]

On the LS, the gas gauge, temp gauge, lights at the bottom of the cluster, and shifter position backlighting is all done with standard bulbs. It's just the speedo and tach that are cold cathode backlit.

[92Lex]

Howcome people don't have problems with the cold cathode backlighting flickering or going out?

[Lexls]

Howcome people don't have problems with the cold cathode backlighting flickering or going out?

←

They do and these problems usually surface when it gets cold. The LS backlighting can definitely go out, and usually does for 93-94 models. It's not that the lamp breaks, it's that the caps fails. For some reason, maybe to cut costs, it seems that Denso started using lower quality capacitors in 93. These didn't hold up as well, especially in the cold. In the cold, clusters will be half lit up or not light up at all. The 93-94 clusters have this problem but the 90-92 clusters usually don't.