This has happened to me since I did an LED conversion, all you have to do is pull the climate control unit out, and re-tighten the bulbs, they are lose (tighten with a small phillips head screwdriver) They are usually little blue plastic things on the top (at least in my 5th gen) :bigok: . When you hit it, and in the past have come back on, you are remaking the connection, now they have jarred far enough off that you can no longer hit it to jar them back into place.

EDIT: after re-reading this, I noticed its the little light above the button. I am not sure where this light is.