Well, my '06 Matrix had the one light go intermittent in the heater control area. I took it all apart to get to the lamps. It was NOT easy! Wow! Toyota really made access to these stupid light very hard. I wanted the whole white box out of the car so I could more easily look at what's going on in there. So I disconnected the two mechanical cables (heater temperature and airflow position) and two electrical connectors. I had to take the glove box out and go from the passenger side to pull the temperature cable. Not fun! But once all that was done I was able to have the box in my hands and the lights came out super easily from the back. Sure enough they were both intermittent and performing all the removal operations finished them off. Not wanting to ever have to do this again, I decided on replacing them with LEDs. I looked online and there are some options on Amazon and other places, but it will take a few day to get here and some reviews were not great about the quality of light and such. I happen to have two reels of LED strip lights that can be cut into sections of three LEDs per section and they just happen to run on 12VDC. Each section has three white and three RGB LEDs. How convenient! I cut two sections and arranged them in the white box, wired them up so that white would have a slightly lower voltage (resistor in series) and red would glow full force, blue and green are off. I used the base of one of the burned out bulbs to make a power connector for my LED wiring and experimented with a few arrangements to see what looks better. I ended up with what's in the pictures. I used double-sided tape to attach the strips to the inside of the box and also used it for some strain relief on the wires and to keep things neat. I seems to work fine, though I have not used in the dark of night yet. The red and white LEDs provide good color, similar to the rest of the dash.
I will add more pictures later as it seems 5 is the limit.