Radio Backlighting Is Out

[95LS400Bob]

95 Lexus Ls400 radio backlighting is out. Display is fine. Anybody fixed this and does a 95 use bulbs or LED's? Thanks!

[VMF]

i'm not sure myself, i remember there was an article on how to change those lights and they were leds, but it might be little lighs as well.

if some1 out there still has the article that was lost in the crash pls respond!:)

[95LS400Bob]

We'll know shortly. I am going in and find out. I'll report back.

Update: There are 2 bulbs in the display. Both soldered in. One of the members here posted way back that radio shack 272-1092 or similar bulb would work.

I desoldered the bulbs and tested them and they are good. So not a bulb problem.

Haven't found the problem thus far. Seem to have continuity at the cable plug in and at the bulbs.

[95LS400Bob]

Well, I gave up and put the unit back together and in the car. What I need now is a wiring diagram so I can figure out how this deal works. I believe all the radio is without lights and all I know at this point is it is not the bulbs.

Any ideas where I can get a wiring diagram?

[VMF]

i have a wiring book, i will check it when i will get home in 1 hour

[VMF]

oops

just checked the book and they have only external wiring, no thing about whats inside of the unit:(

sorry

[95LS400Bob]

Thanks for looking. I'll go back in later on and see if I can figure it out. So many wires, so little time.

[90LS400Lexus]

Is this only a problem on the 1995 and newer models? I have never heard of any radio lighting problem on the 1990-1994 models. Seems like the 95+ got some of the same parts that the 90-94 climate control LCD's got. LOL. Just kidding, because I guess everyone is referring to the actual numbers going out, rather than the entire LCD blackening? Still strange that the problems seemed to have "flip-flopped" on these cars. <_<

[95LS400Bob]

With all the searching the forum as I have done. seems there are a lot of 95 and 96's out there that have lost radio backlighting. There's a lot of little bulbs in there and kinda hard to believe it is just light bulbs. I know mine tested all good. Unless this is some sort of old Xmas tree light circuit (ya know..one goes out and they all go out) then something else is the cause. One of the members here also said his would work sometimes...sometimes not.

Since this is the first Lexus I have had and mine has been out since I got it..I don't know what correct operation is.

The following info would help: Someone with a working unit (95 or 96).

1. Is your radio backlighting on anytime the ignition key is on?

2. If the radio is OFF...but the ignition key in ON....is there any backlighting?

3. When the headlights are turned on in the daytime...does the backlighting in the radio dim?

Trying to find how how this circuit is directed. Thanks.

[95LS400Bob]

I have fixed all the lighting in the radio. I made a whole new circuit for it. I'm posting this so you know that 95's and up have the problem and it isn't just bulbs. It's a problem with the board. I did find one place on line that repaired the backlighting for $200.

Bectha my circuit lasts longer than theirs did. Took a lot of time.

[Great92]

I have a radoi backlighting probelm now with my 92. I have to replace the A/C LCD and thought that I would do the radio at the time. Is the Radio Shack bulb number the same for all years?

[VMF]

hey, in my case i just have couple of them not workin

buttons 7-8 dont work, trac button light is not working as well as another one (forgot which one).

what do you think it is in my case? i didnt investigate this problem myself since it doesnt really bother me that much but since you are at it i would like to hear your opinion.

[95LS400Bob]

Not sure on the 92 if they are the same bulbs. Do a search as I am sure someone has done one.

On the 96, that will be the same dealio as mine. Sounds like you just have a couple bulbs burned out. I din't get under the buttons...but sure they are the same soldered in dealios. Easy to solder a new bulb in.

Like I say...all my bulbs were good..just something in their circuit that kept everything from working on mine.

I took a few pics of mine apart...might help you.

You can see the backlight bulbs. The other bulbs are in the other face section of the radio shown in the background.

[chubyball]

Hey Bob,

Can you show what you did with your new circuit? Thanks

[95LS400Bob]

Best way I can describe what I did was to isolate the lights from where they were on the circuit board and the run in a new wire to operate all the bulbs. You have to break the leads in the circuit board to the lights by scratching across the path so there nothing can backfeed into the board. If you are going ot do this then I think I saved a copy of which leads on the board went to which lights. It takes a lot of time to trace the leads.

[albyone]

95LS400Bob - Could you please post what lines need to be repaired. I have a 95LS400 with the radio backlight problem - all the lights of the radio have gone out - they did come on again for a month or so, but then they died again. Thanks for your help. :D

[95LS400Bob]

This fix is not for the faint of heart. You have to remove the radio and diasssemble it. My notes say there are 10 lights plus the control knob lights. They are numbered at the bulbs.

On the light board you will find printed ciruits:

ILM2 = that lights 12,13,14.

ILM3 = That lights 915,916.

ILM1 = that lights all the control knobs.

ILMDS1 = that lights 903, 904,905

ILMDS2 = That lights 907 and 908.

You have to run a new power line to those circuits and then scratch (through to the copper) those numbered lines on the board so no power will feed back through the original circuits.

Difficult to explain but get it apart on a table...take pictures if you get lost...help you all I can. I should have taken pictures and made diagrams but I was feeling my way along thinking I would find the simgle culprit of why all the lights were out. Instead it was better to just run new leads.

[acw]

Guys, I have not logged on for a while since I sold my 96 ls 400. I just notice that there was a problem with the lighting in the radios and decided to share the solution with you since this forum has helped me out in the pass expecially vmf and vbdenny. I had a radio where the display did not work but the radio light worked. I email some guy on the internet and told him that I was a EE and wanted a schematic and maybe some help and he told me to send the radio and it would cost over $200. I was *BLEEP*ed and decided one weekend to take the radio out and start troubleshooting. I replaced the led assembly and it worked fine but three months down the rode the radio lights stop working. Read below to see what I did next.

Problems:

1. LED looks distorted or missing numbers. Take the radio out and look for the KEX number on the radio and order the led assembly from pioneer. About $90-$105

2. If a few lights are out then you will have to replace the bulbs. About $7.32 each

3. No lights working. This is a good one because it happened to me.

---solution, because the Lexus radio generates some much heat, some of the solder point become loose. Especially around the power supply. there are a few very very small resistor that are hardly connected and causes the light to not work. Solder these two resistors and the lights work. If you should ever have to change the display, then I would recommend soldering these contacts at the same time.

Also remember to solder all the big transistor too since there is one that controls volume also.

Since then, I have repaired 6 radios (95-2000) with those problems and they have been working fine with no problems for a year.

I am working on a CD player now and it doen't seems that hard to fix either.

Hope this helps.

[99lsguy]

Guys, I have not logged on for a while since I sold my 96 ls 400. I just notice that there was a problem with the lighting in the radios and decided to share the solution with you since this forum has helped me out in the pass expecially vmf and vbdenny.  I had a radio where the display did not work but the radio light worked. I email some guy on the internet and told him that I was a EE and wanted a schematic and maybe some help and he told me to send the radio and it would cost over $200. I was *BLEEP*ed and decided one weekend to take the radio out and start troubleshooting. I replaced the led assembly and it worked fine but three months down the rode the radio lights stop working. Read below to see what I did next.

Problems:

1. LED looks distorted or missing numbers. Take the radio out and look for the KEX number on the radio and order the led assembly from pioneer. About $90-$105

2. If a few lights are out then you will have to replace the bulbs. About $7.32 each

3. No lights working. This is a good one because it happened to me.

---solution, because the Lexus radio generates some much heat, some of the solder point become loose. Especially around the power supply.  there are a few very very small resistor that are hardly connected and causes the light to not work. Solder these two resistors and the lights work. If you should ever have to change the display, then I would recommend soldering these contacts at the same time.

Also remember to solder all the big transistor too since there is one that controls volume also.

Since then, I have repaired 6 radios (95-2000) with those problems and they have been working fine with no problems for a year.

I am working on a CD player now and it doen't seems that hard to fix either.

Hope this helps.

←

acw,

Does the "sodering" of the resistor(s) help bring back the LED's at all? My LED's for the Radio/CD/Min/Sec display are missing several "segments"........ Or does the LED unit just basically fail over time?

Thanks, 99

[acw]

99, my fault. The LCD and LED are two different things. I meant to say replace the LCD assembly (has the cd disk number , radio station etc) and the LED are the light behind the number, knobs....

The LCD and LEDs go bad after a while. Hope this helps.

acw

[99lsguy]

acw,

Thanks - its the LCD assembly that is going bad for me ; and...

Like you say, while your in there, might as well get the LED's too (backlights)

Looks like the $150 for Mikado to do the LCD assembly is the way to go....

Good Info!!!

[95LS400Bob]

I have something to add to this thread for the next guy who has his radio lights go out. On a recent trip out of town I started losing the radio lights one by one. Guess their lifetime was up. Since hindsight is 20/20.....I should have replaced every bulb in there while I was in there the first time. So...learn from my mistakes.

There are 13 soldered in bulbs. These light the radio and switches. Radio Shack #272-1092 works perfectly as a replacement.

For the LED backlight there are 2 larger bulbs. Mine were still working but I wanted new. I ran all over and finally found a substitute bulb. That was Radio shack # 272-1141. They are a slight bit dimmer...but will be hard for you to notice the difference. These are bulbs...not LED's. All bulbs are 12 volt.

It's a little tedious soldering in those places but I am no expert at soldering and I made it through it. Be careful with the little green covers on the bulbs. Easy to tear them.

Here's a link on how to pull the radio out of a 95. http://carstereohelp.com/stereoremovalLexusLS400str1.htm

[mrc]

I have fixed all the lighting in the radio. I made a whole new circuit for it. I'm posting this so you know that 95's and up have the problem and it isn't just bulbs. It's a problem with the board. I did find one place on line that repaired the backlighting for $200.

Bectha my circuit lasts longer than theirs did. Took a lot of time.

Hi there, I would love if you could provide pictures or schematics of your fix. My radio works fine with the exception of backlights.

[1990LS400]

I have fixed all the lighting in the radio. I made a whole new circuit for it. I'm posting this so you know that 95's and up have the problem and it isn't just bulbs. It's a problem with the board. I did find one place on line that repaired the backlighting for $200.

Bectha my circuit lasts longer than theirs did. Took a lot of time.

Hi there, I would love if you could provide pictures or schematics of your fix. My radio works fine with the exception of backlights.

This thread is 10 years old so I doubt if the original participants are going to reply. It must not be very difficult to replace the backlights on the radio since the California company that added a 3.5 aux-in port to the back of my 00 LS400 radio for $85 replaced both backlight bulbs for only an additional $10. The company that did all that is: http://factoryradioservice.com

[steve2006]

Backlight fix below.

BackLight audio stereo ls400 - UCF20 - dry resistors-3.pdf