[Alan Anderson]

You do have the switch connected between ground and signal, right? And your wires go to the COM and NO pins on the switch, right?

Because of the pullup resistors on the Digital Sidecar's DIO pins, a Normally Open switch will read True when it's not active, and False when it is, so it looks like you got that part correct.

How are you using the switch value to zero the motor control? Show us that part of your code; it sounds like it isn't working properly.