I don't know about the navigation equipped models but the standard center display showing the various controls, etc., on the '03 model years is LCD without a doubt. Just run your finger across the screen or press your finger on one of the display icons if you have any doubts.

 

I don't know about the screen without navi.
Maybe it is LCD.
But the screen with navi is definitely CRT.

 

1) Actually, the brightness INCREASES very slightly when the headlights are turned on, which is counter-intuitive.

2) No change rotating the dimmer control (the dimmer control ONLY affects the instrument panel lighting). The center display is controlled by a left/right rocker switch just below the screen,above the radio/HVAC controls.

3)DISPLAY settings? You mean like the MPG computer,radio, or when adjusting the HVAC controls? If that's what you mean, no. They do not affect the brightness.

 

Yes-It's pixels that react to finger pressure as you say in our '03 (and we are non-navigational).

It's kind of a weird display, though, because it's a bright white background with medium blue characters and symbols, not unlike a laptop computer screen. The 7 step brightness control vary the the white background brightness level and the brightness of the characters.

The other LCD screens I've had in cars look very different. They seemed to use a darker background with brightly lit characters.

 

You may check the illumination circuit on the LCD screen, and finally-the unit might be gone. If you have a chance to check with other screens will be good. There is good few reasons for being dim, and without seeing the car is hard to tell. I will think for something else meanwhile.

 

I may have understood it wrong ...
Does the the screen start dim and then brightens up

OR

The setting (brightness) gets lowered.


The first can be voltage/temp/age/environment issue while the second has more do with memory.

Salim

 

The LCD screens tend to dim in freezing conditions, but if no reaction to adjustments, may be checked for bad soldering as well.
As I said, if you have a chance to swap the screen with working one, it will be the easiest way to see where exactly the problem is.
I believe you can get one of eBay at good price (like this)
http://www.ebay.com/itm/99-03-LEXUS-...9VNX~l&vxp=mtr


or


http://www.ebay.com/itm/2002-LEXUS-R...xWSLAX&vxp=mtr

 

OK, a couple of things-

The dimness with cooler weather could just be a coincidence, and the cooler weather I spoke of never approached even freezing temps (maybe 40 deg or so). That's "cold" in AZ terms, anyway.

As to the brightness of the screen w/ headlights turned on, I discovered that the screen brightness selected with the headlights OFF is retained, but if one turns the headlights ON, and then sets the screen brightness lower, the system "remembers" both settings, and applies them when the headlights are turned On and OFF as appropriate. I never knew that before.

The symptom appears to be very constant now, and that is the screen brightness is dimmer than it should be for 7 Bars (full bright setting), but it's usable in most lighting situations (but not as bright as it used to be possible to make it). In the last couple of weeks, it hasn't changed its own setting, or gone dark (winked off) at 2 or 3 bars of setting as it did at one point.

 

That's a reasonable price for troubleshooting (especially $65).

The situation for new appears to have stabilized in a "usable" condition, so will probably monitor it for now until it gets unusable as some other life-issues have come up.

Funny how priorities can change depending upon the life-stressors we humans are experiencing!

But it's nice to know these are common enough used that I can probably snag one for a reasonable price should it get worse (which I am sure it will).