I have the same problem , I went as far as opening up the HVAC unit and found there is a total of 5 green bulbs that are used for backlighting the buttons. Not the little green light that appears above the button, but the back light for the symbols on the buttons themselves. Only about 1/4th of my HVAC lights come on now! Doh! The bulbs are like $4 or more a piece at Toyota if I remember correctly. I have yet to change mine, they just seem to went out when I had the dash apart. They still look in good condition , the filiment still looks in one piece. Anyways, hope someone can help.