Master Window Switch: Driver Window Doesn't Work

I have had the master window switch on the 2000 Jimmy worked on. They cleaned the connections and the driver's side window worked for a couple of months. In May, the driver's side window stopped working again. I purchased a master window switch from a "junk" yard. The driver's side window still would not work. Everything else worked on both switches. I read the one thread about none of the switches working on the master window switch. They suggested that the wire (s) may be broken in the rubber sleeve between the door and the body. Does that apply to my situation? Any ideas would be greatly appreciated. Which color of wire am I looking for in regard to the driver's side window?