I've had to pop out the 4wd selector switch unit thing and leave it partially sticking out. Once in a while I'll get in the Suburban, and after starting the engine the Check 4WD light will be on. I knock the module a little bit, turn the truck off and then back on and normally the light will be off. I also had it at one point where I used the 4WD.. the 2WD wouldn't pop back on afterwards. I had to pull the module out and wiggle the wires a little bit and then push the 2WD button to make it work. Am I looking at a new switch module? Anyone else have the problem before? I think I read a post here before about this issue.