Yup, 5 way switches wear out and/or break, especially stock ones. They're not usually the highest quality.
Does the switch make any crackling type of noise when you switch between pickups? If so, it may just be dirty. You can go to Radio Shack, get some contact cleaner and spray it into the switch.
If it's not really making noise when switching, pop off the control
cavity cover and make sure all the connections look good. If the connections all look fine then just get the switch replaced.