[Mark McLeod]

Which example are you referring to?
The simple limit switch example won't run the sequence you were talking about originally. That's what Stephen's code does.

In that original limit switch example, if you want to use a button instead of the joystick axis, then you'll need to use the button to choose a motor speed to put into the coercion vi.
The broken wires are because the upper and lower limit wires are carrying floating-point numbers, while a button is a boolean True or False.