I keep finding more info on this way to Disable the Passlock utilizing a switch. The following bulletin is from GM on this exact modification. We are just accessing the "Yellow Passlock Data Wire" at a different point than they are on the trucks. Interesting, huh? Maybe this is the same modification that bcopeland had on his 99 Malibu?
http://www.gmupfitter.com/publicat/bull/bull26.pdf