Hello. I own a 1992 LS400. I noticed today that my center console, odometer and radio display started to not light up today when driving at night. Only my instrument cluster, A/C and climate controls light up at night. Has anyone else had this issue? And if so...is this just a simple bad fuse that is the problem? Any information would be helpful in this. Thanks

 

Haven't had this problem but I have one radio bulb out on my 91.

It's quite possible that you have several bulbs out. I assume this is the stock radio and that your radio is working

When you say climate controls light up at night, you mean the backlighting for the LCD display and the buttons?

Given that those work when you turn the headlights on, I assume that your circuit is fine and that the backlighting is responsive to your headlight switch

The odometer bulb is wired to the instrument cluster, so I suspect the problem is with that bulb since the panel is working.

Here is a test - with the headlights on, turn the dimmer switch counterclockwise for the cluster, and see if the cluster dims. If it does, then this would indicate to me that the cluster is aware that the headlights are on, and I would expect the bulb for the odometer to be the culprit. The cluster backlighting should be unresponsive to the dimmer switch when the headlights are off.

Pictures would be helpful.

Another former owner that had one bulb out in the climate controls:
https://us.lexusownersclub.com/forum...&comment=24977

 

Hi! Thanks for your detailed response. I have to say, I took my car to a Lexus specialist and I NEVER had this problem before until I got my car back from the shop. I asked them about it and they just told me they switched out the "NORM" bulb in the instrument cluster because it was burned out. I was getting work done on my air suspension. So...basically after they worked on my car...my brightness **** on my instrument cluster no longer works. I cannot dim it like I used to. It just stays at the brightest setting. So, between that and not having the odometer light up, center console light up or the backlight to the radio/cd display light up, it is very frustrating trying to figure out what the problem is. Let me ask you this, on your 91 LS, if you turn the dim **** to the very left on your cluster, does the center console, radio display and odometer turn off? Please let me know. Thanks. I think that will help me pinpoint my problem. I don't think it is a fuse.

 

Ah, that's an important detail to know

The dimmer switch on both of my cars controls the brightness of the instrument cluster and the backlighting brightness of the odometer, climate controls, radio, shifter illuminated panel, etc ONLY when the parking lights or headlights are on

It sounds like it might be worth removing your cluster to check if a pin or wire was broken. Your dimmer switch may also be disconnected for some reason. It sounds like your cluster is unaware of the headlight switch position. This doesn't necessarily mean there's a problem with your combination switches or the cluster, but something in between is wrong

Removal steps for cluster (suggest putting masking tape on all of your tools to prevent damage to trim):
http://www.lexls.com/tutorials/elect...ntcluster.html

A few other questions -

1- When you turn on the high beams, does the blue high beam indicator illuminate on your cluster at the top? Do the turn signals still work? (Just curious)
2- When you got the car back, were there any warning lights on the dash, like the Air bag light?
3- When you put the key in the on position, do all warning lights still illuminate on the cluster?

 

Hi. To answer your questions, Yes. The blue high beam indicator lights up still at the top. Turn signals still work. No warning or air bag light came on in the dash when I got it back. When I put the key in the ON position, all Warning lights illuminate on the cluster like normal then disappear after a couple seconds.

 

Hi. To answer your questions, Yes. The blue high beam indicator lights up still at the top. Turn signals still work. No warning or air bag light came on in the dash when I got it back. When I put the key in the ON position, all Warning lights illuminate on the cluster like normal then disappear after a couple seconds.

 

Ok great to know. So I think it's time to start testing the dimmer switch, aka the "rheostat light control"

Please read below - this will require some basic electrical knowledge like how to use a multimeter to check for resistance and voltage.



Looking at the troubleshooting chart (below), your issue seems to fall into 2 conditions:

- Illumination lights with adjustable brightness do not light.
- Brightness does not change when rheostat volume is turned.

The chart shows this could be a problem with the dimmer switch / rheostat control, the wiring to the instrument cluster, or the cluster itself. I would check the easiest things first - your dimmer switch and the wiring for your cluster (which could have gotten pinched when the unit was reinstalled)



You will need to remove the panel with the warning lights and dimmer switch first. Follow steps 1 - 7 and disconnect the battery once you've moved the steering column out of the way:
http://www.lexls.com/tutorials/elect...ntcluster.html

Note that connecting the battery and turning on the car with the warning lights bezel disconnected will trigger the air bag light. LexLS has steps to turn that off if you accidentally do that.

Here is how to test the rheostat control once you have access to the connector:



Here is the wiring diagram for extra info:

 

Thanks for the information 👍🏻

 

If your dimmer switch / rheostat control tests fine, then it's likely something in the wiring to your cluster or dimmer switch, or the cluster itself has an issue after the repair was done, based on the troubleshooting chart

 

Update - Solution was that dimmer switch needed to be plugged back in

Source:
https://www.clublexus.com/forums/ls-...l#post11632659