Since there have been no other responses, I'll take a stab at it.
I don't know if there is a replaceable bulb but that would be the first thing to look for.
If this is the only switchplate that the lights quit working on, I would think it is a broken wire/loose connection if not a bulb. I would check the connector at the switch to make sure it is still in place and not corroded. You could try a test light at the lighting connector/wire with the lights on to see if there is power there.
If there is no power at the light connector, you probably have a broken wire between the body and the door. There is a harness that sees movement every time the door is opened and closed. I haven't had the opportunity to look for broken wires on my Explorer but I have fixed many other cars with power windows with this problem.
I will try to find a wiring diagram for this circuit and put a copy of it here.
Good luck,
Mike