I was going to say to just replace the light bulb, but I just looked at a spare switch I have (it also does not illuminate with the dash lights). Looks like unsoldering a small pc board to take the switch apart is necessary, think I'll pass and keep it as a working spare.
By the way, other switches not illuminating can be repaired (if you care) by replacing the small light bulbs inside with a radio shack light bulb, 272-1092
