Bad Fog Light Switch?

I just bought a 2001 Yukon XL and the fog lights are not working. The previous owner stated he asked the dealer about it, but they stated they couldn't find the problem without tracing the entire system. I'm not getting light to either fog light and the switch will not even light up. It is the dual fog light/rear wiper switch. Has anyone had the switch go out? Can someone with a factory service manual tell me which wires to the switch are for the fog lights? Any insight is greatly appreciated!