I think the knobs pull straight off, and there might be a nut behind each. Once those are off, the plastic trim piece will pop right off (pry carefully), and you can disconnect the AC controller. Behind it you'll see what looks like an octopus. At the head of the octopus is a bulb, and each "tentacle" is a fiber optic light channel that transmits light to the upper switches (which in your case aren't lighting up). Either the bulb is burnt out, or the tentacles came out of the switches.