mrdiego

1991 Ls 400 Instrument Panel

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My 1991 LS 400 display panel blacked out. In addition, the spedometer, the gas guage, tachometer etc is not working. I thought that the fuse blew out but I checked it and the 7.5 amp fuse is good. Any idea what is causing this?

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One of the most common problems on your model series. Do a search and you will find tons of postings relating to this problem. Also, at the top of the page, look at the "sticky" about the instrument needles. Sounds like you need Jim Walker's help.

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I just did this repair on my '94 LS

I got the info from this site some time ago and saved it.

I think the original post was by Cole Carter.

You have to change three capacitors, it's not too hard a job if you can solder

small parts successfully. The originals are v. small surface mount and you have to be careful not to pull the track up from the board.

All the info is on your site and it works perfect. B)

Cost of parts US about 2 dollars max.

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What capacitors were they?

Anyone have any luck on the sticking tacho and speedo's?

I am going to do this. Just dont power car when panel is removed.. I hear the airbag light comes and stays on.

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I will do this for 2 bucks.. After soldering high tech Air Force components for many years I can do this!

Cheers to LEXUS and long live the LS

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These capacitors do are not soldered from below the circut board???

Okay its all out on my table and ready to go, but I think I am going to bring to TV repair guy.

As for the capacitors them selves they can be higher voltage & uf, but not less?

Hello Folks,I think I have an answer to the Instrument Cluster Light and fuel gauge problem on older LS400's.If you have the common problem with the instrument lights whereby they don't come on right away when you start the car in the morning when its cold .... then its probably an electrolytic capacitor located at C212 on the small PC board on the back of your instrument cluster.If you also have the common problem whereby your fuel gauge takes a long time to read the fuel level in your tank after starting your car in the morning and/or the reading is much lower than the true amount of gas in your tank, then its probably two electrolytic caps on the "Big" PC board on the back of your intrument cluster. One of the caps is located at C142 on the big board... and the other is located at .. C147 . The interesting thing is that these caps are all the same style. They are very small (Low quality) electrolytic caps. They are housed in little metal cans ... with very short leads .. although they are not true surface mount caps. I tested a bunch of caps on the small board and found that only this type of capacitor was disfunctional .... and interestingly enough .... all the caps of this style were bad on both boards ... (A total of 3) .... If you are scientifically inclined .. I need to warn you that these capacitors often do not "crap out" unless they are cold .... If you read the capacity at room temp they may or may not seem fine ... But when you put a chiller on them ... then the capacity reading starts to approach zero ...What you should do is replace them with better quality caps .... either bipolar ... or ceramic .... or titanium ... You can go higher in voltage and also higher in UF .. it doesn't matter ... except for maybe the one located at C142 ... I am not sure .. but this one may provide some kind of timing function ... the other two are clearly just filters .... (IE: for Ripple)...C142 (big Board) was 4.7 UF, 25VC147 (Also on the big board) was 10 UF, 50VC212 (Small Board) 10 UF, 16 VNow both problems are fixed ..LamSV was very helpful in getting me focused .... I would still be stuck without him ...Remember .. that you need to disconnect the battery before you start removing stuff .. and wait a couple of minutes ... I made the mistake of not doing this and my Airbag warning light would not go out ... So I removed the little light bulb that warns you ... I am not sure my airbags work after 10 years .. but my guess is .. they work or not ... regardless of whether there is a bulb in the warning light circuit ...This problem is very easy to fix for anybody comfortable around a soldering iron .. and much less expensive than having the dealer replace your boards ... (My cost was about $1 worth of parts versus $1200 if the dealer fixes it) .... the labor involved was mostly in removing than reinstalling the instrument cluster ... (About 1 hour) ... Replacing the 3 capacitors is about 45 minutes worth of work ....Best of luck to anyone with the problem ..... Cole

POST FROM COLE GUY

Broke the little plastic piece on the bottom of capicator... Suspect its not essential... Maybe hope.

As for taking everything apart.. I utilized a screw driver for the initial plastic piece in front of assembly... The connectors are a pain.. The back orange one is the worst and when you take out the whole cluster you have to sorta twist and start to remove.. Then one has to remove connectors...

Over all there is about 20 total screws so put them in bags or something... ALSO take your time.. I get wound up over stupid connectors, but for the most part held my kewl!

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I have extra capacitors so if you have trouble finding them I can send....

Cold nasty solder joints all around.. Cheers to a horrible soldering job!

Practice before you try to do this...

For sure if you can get an expert to solder the capacitors on the board for 20 - 30 bucks do it.. I bought about 15 dollars worth of supplies and would have rather an expert solder the board.. Then you dont have to worry about heat or damaging the board (pull up terminal or something else during removal or soldering)..

Job took about 3 hours.. Looks like everything is good since it all lit up! Cheers.. Say a prayer at the end..

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Perhaps posting the LS model years the instructions above are good for would greatly help.

I take it that the instructions are for 93&93 LS only?

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it took a little digging but I found it...

Here it is again, for all those with the same problem and can solder....

I'll let you know how it worked for me!

I tried to download the attachment, but could not, can you Email it to me??

Thanks Jerry

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Mine just went out on my 93 LS400 also[in the mornings]--I can't find the Cole fix--used to be photos, etc on this. can someone email to me also-or paste in a new post. having problems finding anything.

Richard

[tansupplyman]

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Found this in my saved Lexus email-the links work:

purportedly, the 'light-out' problem in cold weather only happens to Gen1 90~94. I believe yours is the first one we heard for a 98.

for 90~94 models, the problem is a bad 50-cents capacitor (C212 16V/10uf) on the main circuit board inside instrument cluster.

http://apaqdigital.com/ls400/instrument_circuit.jpg

http://www.clublexus.com/forums/showthread...mp;pagenumber=6

but more than likely the circuit board is different on 98 model, so contact the ebayer on this item:

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...item=2452608356

see whether they can handle a 98 LS400. they only charge $175.

or check with Jim Walker using this form for help:

http://us.lexusownersclub.com/forums/index...E=4&MID=587

also found this:

Hi Folks,

been super busy in last couple of months, hardly had chances to visit the forum. hoped everyone had a wonderful x’mas and new year.

I finally got a chance to tackle the fuel gauge problem on my 94 LS. before the fix, the fuel gauge needle could only go up to 1/3 max even tank was full. so I followed the instruction found here to replace C142/C147 electrolytic capacitors on the big circuit board inside instrument cluster. I’m happy to report it works like a charm! the fuel gauge is back to normal.

*removing cluster and the 3 darn connectors

of course, you must follow Jim Walker’s infamous procedure:

http://www.lexusownersclub.com/Lexus_Circu...ard_Removal.pdf

I found that the biggest pain in the butt was to disconnect 3 connectors (blue, white & orange) from the back of cluster so that you could take the entire cluster out of the car. on each connector, there is a latch to hold the connector tight in the socket. one will have to manage to press the latch inward and pull the connector out at the same time. it was much easier to say than getting it done because there is very little room behind the cluster and the connectors are pretty darn tight. you need to have lots of patience with very strong fingers too!

*removing old capacitors

when you have the bare circuit board on your bench, and begin to remove the bad C142/C147, DO NOT just pull the capacitors out. Be very careful not to damage the circuit trace surrounding them. the capacitor can is surface-mount on the component side of circuit board, and you can’t de-solder it from the bottom of circuit board. the two legs (+/- leads) are too short (entirely covered by the ‘can’) to be de-soldered underneath the capacitor can. What I did was to use a sharp nose pliers and ‘destroyed’/removed the capacitor can first, then the two leads were exposed to be de-soldered.

*new capacitors

the soldering work was not difficult to do, one just needs to use very fine soldering tip and keep your hand steady. the C147 is rated 50V/10uf, and C142 is 25V/4.7uf. however, I couldn’t find 25V/4.7uf at Radio Shack, so I used their 35V (max)/4.7uf, and it works!

(note: the ‘V’ really stands for WVDC). pay attention to the orientation of +/- lead from capacitor can. usually, the ‘-‘ lead is aligned with white band on the capacity can.

*my remaining issues:

1. oil level warning light is on despite engine oil is indeed at proper level. does anyone know which capacity is to control this warning light? in fact, does anyone have a circuit layout or wiring diagram for the instrument cluster?

2. the coolant temp gauge remains bad on my cluster. I believe it’s the needle itself, not any bad compoenent on circuit board. when I lift other 3 needles (fuel/rpm/tach) by finger and let go, they will return the lowest position immediately in smooth motion, but temp needle won’t do that, it just stuck, and the center dial is somewhat loose and non-responsive. does anyone know how to change out the needle/dial?

--------------------

C.W. Lee, Atlanta GA

also found this(all from my saved copy&paste emails-you tend to do that when servers fail):

Hello Folks,

I think I have an answer to the Instrument Cluster Light and fuel gauge problem on older LS400's.

If you have the common problem with the instrument lights whereby they don't come on right away when you start the car in the morning when its cold .... then its probably an electrolytic capacitor located at C212 on the small PC board on the back of your instrument cluster.

If you also have the common problem whereby your fuel gauge takes a long time to read the fuel level in your tank after starting your car in the morning and/or the reading is much lower than the true amount of gas in your tank, then its probably two electrolytic caps on the "Big" PC board on the back of your intrument cluster. One of the caps is located at C142 on the big board... and the other is located at .. C147 .

The interesting thing is that these caps are all the same style. They are very small (Low quality) electrolytic caps. They are housed in little metal cans ... with very short leads .. although they are not true surface mount caps. I tested a bunch of caps on the small board and found that only this type of capacitor was disfunctional .... and interestingly enough .... all the caps of this style were bad on both boards ... (A total of 3) ....

If you are scientifically inclined .. I need to warn you that these capacitors often do not "crap out" unless they are cold .... If you read the capacity at room temp they may or may not seem fine ... But when you put a chiller on them ... then the capacity reading starts to approach zero ...

What you should do is replace them with better quality caps .... either bipolar ... or ceramic .... or titanium ... You can go higher in voltage and also higher in UF .. it doesn't matter ... except for maybe the one located at C142 ... I am not sure .. but this one may provide some kind of timing function ... the other two are clearly just filters .... (IE: for Ripple)...

C142 (big Board) was 4.7 UF, 25V

C147 (Also on the big board) was 10 UF, 50V

C212 (Small Board) 10 UF, 16 V

Now both problems are fixed ..

LamSV was very helpful in getting me focused .... I would still be stuck without him ...

Remember .. that you need to disconnect the battery before you start removing stuff .. and wait a couple of minutes ... I made the mistake of not doing this and my Airbag warning light would not go out ... So I removed the little light bulb that warns you ... I am not sure my airbags work after 10 years .. but my guess is .. they work or not ... regardless of whether there is a bulb in the warning light circuit ...

This problem is very easy to fix for anybody comfortable around a soldering iron .. and much less expensive than having the dealer replace your boards ... (My cost was about $1 worth of parts versus $1200 if the dealer fixes it) .... the labor involved was mostly in removing than reinstalling the instrument cluster ... (About 1 hour) ... Replacing the 3 capacitors is about 45 minutes worth of work ....

Best of luck to anyone with the problem .....

Cole

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Earlier this year I replaced I replaced C212 on the '94 for the blinkidash problem. Today I replaced C142 & C147 on the '93 for inaccurate fuel gauge/intermittent speedo problems (replaced C212 while I was in there).

I did not disconnect the battery, but I made sure that with the ignition in the "Lock" position 90 seconds had elapsed while I removed the bezel and screws prior to pulling the harness connectors (per manual).

The caps friction fit on to prongs soldered to the board. After lifting off the caps I used small needle nose pliers to grasp the prongs, applied the iron to the prongs and pulled them loose. Then I slipped the plastic cap insulators off the board to expose the actual solder pads on the board.

I clipped the leads on the caps to about 5/16" (they are noticeably taller than the originals) and soldered them directly to the pads orienting the lead on the striped side of the cap with the negative pad on the board ( "-" is labelled on the board). The 5/16" allows access for soldering and some flexibility to lean them out of the way when mounting the small board back on top of the larger one.

The caps were normal stocking items from Radio Shack. Part numbers 272-1025 (qty 2) and 272-1024 (qty 1) at 99 cents each. The voltage rating does not match, but that is a maximum rating (35 VDC).

The '94 has had no further dash issues and the '93 worked fine on the test drive and fuel fill-up today.

Used Meguiars ScratchX and a microfiber towel to clean and polish the meter lens inside and out.

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seems an excellent idea on the ScratchX on the plastic instrument panel[think that is what you did]--did it remove the scratches?

tks

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It removed the light swirls so that all that remains is a few deeper scratches which are near the edges.

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Hey to all. Just wanted to say thanks for the useful info about replaceing the 3 caps. I have a 93LS and I still have a problem with the clusters. The replacement of the caps did the job as far as the needles being on, and fuel gauge, but still have the background lights not on. I don't see my numbers. Any suggestion will greatly help.

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Yes, the dimmer functions well. All the fuse are fine and I just wanted to know what cap is in the line for the background lights. Or if it's even a cap or something like a diode or transistor????? Thanks for the help and good respones time.

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Hello Folks,I think I have an answer to the Instrument Cluster Light and fuel gauge problem on older LS400's.If you have the common problem with the instrument lights whereby they don't come on right away when you start the car in the morning when its cold .... then its probably an electrolytic capacitor located at C212 on the small PC board on the back of your instrument cluster.If you also have the common problem whereby your fuel gauge takes a long time to read the fuel level in your tank after starting your car in the morning and/or the reading is much lower than the true amount of gas in your tank, then its probably two electrolytic caps on the "Big" PC board on the back of your intrument cluster. One of the caps is located at C142 on the big board... and the other is located at .. C147 . The interesting thing is that these caps are all the same style.

Hi Folks !!

I' d like to thank you very much for that topic. Today I spend no longer than two hours (inc. combination meter removal) and my fuel gauge and black panel start working ! :D I replaced three capacitors with new ones (with higher voltage) and I'm and my LS happy now :-)

It is very easy to do - only difficult was to remove one capacitor close to pins.

Regards,

Mariusz /Maniek (Poland)

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Hi Folks !!

I' d like to thank you very much for that topic. Today I spend no longer than two hours (inc. combination meter removal) and my fuel gauge and black panel start working ! :D I replaced three capacitors with new ones (with higher voltage) and I'm and my LS happy now :-)

It is very easy to do - only difficult was to remove one capacitor close to pins.

Regards,

Mariusz /Maniek (Poland)

Hey, that's great news! Glad it worked out for you! It's a great feeling to fix a $1000 part for a few hours time and a pocketful of change isn't it? :cheers:

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I cannot locate the C 212 cap or the C 147 and 142 caps on my 91' LS400. ALL MY NUMBERS ARE 2 DIGITS, AND i SEE NO THREE DIGIT NUMBERS. dOES ANYONE HAVE PICTURES OR KNOW WHY i AM HAVING THIS PROBLEM?

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I cannot locate the C 212 cap or the C 147 and 142 caps on my 91' LS400. ALL MY NUMBERS ARE 2 DIGITS, AND i SEE NO THREE DIGIT NUMBERS. dOES ANYONE HAVE PICTURES OR KNOW WHY i AM HAVING THIS PROBLEM?

Because this topic relates to the 93-94 cluster problems not the 90-92 :)

On the 90-91 cluster check out C6 220UF/25V on the top PCB,it is located just above the white 3 plug (CNU) and between the 2 transformers

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