How to repair the zoom control?

I have an S1850 which seems to work fine except for the zoom control. The zoom control switch moves smoothly left to right but does not affect the lens. The camera does not respond to this zoom control at all. The lens will move itself in and out when switching the camera on/off, which leads me to believe that the problem isn't with the lens mechanism. Any idea on how to fix or determine what parts I will need would be greatly appreciated!