Mine was just a dead bulb. I could see the numbers on the display but just barely in ideal lighting situations. I replaced it about 6 months ago. They are little tiny bulbs, I forget the size but there's about 7 of them that light up various parts of the cluster.
You are on the right track. Start with the two lower bolts that are way down there. The panels will still be clipped into place. You have to give them a tug to get them started and they pop off. As you remove pieces, work your way up and you will reveal more bolts.