The backlighting on my A/C switch panel shows only a small glow in the corner; the remainder of the panel is out. Attached pics of the reverse side shows no obvious way to resolve. No bulbs shown to replace.
I think you need to remove the knobs to get at the bulbs, from the front. Can you gently pull the knobs off? You might have to rotate the knob to a certain position before you can remove it. Then hopefully you will find the bulbs.
If you can figure out what kind of vehicle those controls are meant for, you might be able to find a youtube video. My guess would be a Chevy truck, but that's just a guess.
On mine, there is a set screw on the bottom of the knob to secure it.
Rich
Call the number on the tag on the back of the Dash, they can tell you how to fix it, I think you have a bad Dash inverter.