Diagnosis
The cycle selector knob is not engaging properly with the timer (or electronic control) shaft behind it. The plastic splines inside the knob or on the shaft are worn down or broken.
How to Fix It
The knob just pulls straight off. Pull firmly. Inspect the inside of the knob—you'll see a pattern of ridges. If they're rounded or cracked, you need a new knob. The part number is often W11035631. If the knob looks fine, then the issue is with the shaft of the timer/control itself. With the knob off, try to turn the shaft with pliers (gently). If it turns but doesn't click through cycles, the internal timer mechanism is faulty and the whole control unit needs replacement.
If That Didn't Work
If replacing the knob doesn't fix the "skipping," there might be a broken detent spring inside the timer assembly that provides the clicking feel. That's not a repairable part—it's a full timer replacement.
Heads Up
When ordering a new knob, make sure you get the right one for your specific model. There are subtle differences in the graphics and the spline count that won't be compatible otherwise.