Hey folks, I have a 2001 Lexus RX300 and she's a real beauty. The only issue I'm having, is that the back lighting for radio and HVAC controls are very dim. You can barely make it out. The same thing goes for the lit buttons just below the screen. I've already done the obvious and turn the brightness dial to Max, but it doesn't really make any difference. When I'm driving at night, everything has a very faint kind of glow, really dim. I read somewhere that there is something called an electroluminescent panel that is responsible for that backlighting, but I can't find any wiring diagrams or location of that. Sure would like to get these things brightened up! Thanks for any help

 

Your unit looks like this?
https://www.ebay.com/itm/145906027241

 

Are you adjusting the dial at night time .. with the lights turned on?

Salim

 

yes, that's the one

 

Mine does the same thing. It's fine in the summer (warm temperatures) but in the winter (or on cold mornings) its barely visible. An old replacement will probably end up doing the same thing (they are 25 years old, after all).

 

Yep, mine is the same way. I've done a ton of research, and I just haven't come across exactly how the backlighting really works. I've read a lot about the 2001 having actual light bulbs with small covers but it sounds like you have to completely take apart the radio to correct that. The other thing is, if I'm driving it at night, it's not just the radio and HVAC controls that are extremely dim, it's also the window buttons on the doors that have an extremely faint light. My instrument cluster is just fine, all the dome lights work, in fact everything on this car Works flawlessly except this.

 

Does the cluster dim normally?

 

Yes, the instrument cluster is just fine, and all the lights including the center console, respond to turning the dimmer up and down. The only thing is, while the cluster is plenty bright, all of the rest of it is so dim you can barely perceive it. And before I forget, thanks to everyone who has responded. I really appreciate your help

 

The dial is for cluster lights only. [To help reduce fatigue of the eyes when the ambient light is low/dark].

Please expand on 'rest of the lights'. The cabin light? Map light?

LCD is a different thing and that can be impacted by temperature and flaw in the lcd display.

Salim

 

I'm sorry if it wasn't clear. What I'm speaking of other lights, I'm referring to the radio and HVAC units and door window buttons extremely faint. All other Lighting systems work correctly, including the instrument cluster. Whatever is going on, it's affecting the back lighting everywhere that you would expect backlighting to be. Window door buttons, gear shift selector, all of them terribly dim. At first I thought it was just a matter of replacing bulbs or diodes in the center console for the radio and HVAC systems, but the problem is not isolated to that alone, it includes all of those back Lighting systems. I'm doing my best to research, and taking all your fantastic suggestions to Heart. I'll post when I get this figured out

 

This is the purpose of this forum ... collectively help each other.

Is the dial affecting the illumination level of the instrument cluster?

Try locating electrical schematics.

Salim

 

Need to test the output voltage of the dimmer control here's a schematic of a typical Toyota of this era.

 

This is really great! Thank you

 

Does the cluster dim normally?

edit - also see this thread should have some relevant info for you
https://www.clublexus.com/forums/es-...version-2.html

 

I asked the same question but did not get an answer. post #11

Salim