Jeep 1995 Grand Cherokee: Service 4WD switch

Thank you for helping to narrow down the solution, but could you please be a little more specific? First, where is the switch located, and two, how do I know which one it is (or is there only one)? I am not a professional mechanic, but out of necessity, I am learning how to fix some of my problems myself. Is this one that might be considered over my head?

Thanks in advance... Bob