Blue display light stays on all the time. - Hyundai 2008 Elantra Radio

Sounds Like A Defective Lamp Or Balast Assembly..

you don't have to .

I have the very same problem and I have no knowledge of the backlights of LCD panels. Is there any way to fix this yourself?

Without looking at the monitor to confirm this, I suspect you have failing capacitors which power the HT circuit, simply, the power needed to light the display, is leaking to earth, capacitors have lost the ability to store the charge necessary to illuminate the screen, which is why it is working erratically.
You need to get this checked out by a TV technician.

This sounds like the power inverter is failed.. It's what pumps up the power for the light in the monitor.
You could try unplug the sound bar from the back of monitor if you have the sound bar installed. Just a maybe..
To fix the inverter (replace) is usually better to buy newmonitor unless you do it your self.
The defective LCD Backlight inverter will cause the following symptoms:

• No Display, but Power Indicate light stay on green (Or Blue).
• Screen flash on and off and the power indicate light stays on green (or Blue).
• Dim Display

Go here to start looking if you want to try yourself. http://www.lcdparts.net/DI3D.aspx

On the radio...

1. Press the "Menu" key.
2. Press the down arrow until you see "Light" displayed on the LCD.
3. Press the "Select" key.
4. If "BLT ON" is on the LCD, press the up arrow until you see "BLT Norm".
5. Press the "Select" key.
6. Press the "Menu" key.

If your display settings aren't set to automatic this can occur. Example: if you have set resolution to 1080i and are trying to play it on a display that has 1080p you will get a blank screen or no signal message. you will have to connect your PS3 to the last display you had an image on and change the "display setting" to "automatic" for your PS3 to work on all displays. when you choose a specific resolution to the "display settings" it will only work on that specific resolution. hope this helps.

r u sure ur monitor is supported my the motherboard display........ just c whether ur monitor is showing working condition in BIOS

Replace the entire DAC board (board with power suplly going into it) for easiest solution.