[Al Skierkiewicz]

Chris,
We use a calibration program that our crack software team writes up. It allows us to look at the raw data as the sensor is manipulated and when needed allows a calibration routine to set mechanical center or a soft stop. Of course using a pot for arm position or steering position is easily checked with power on for 0- 5 volts or with power off with an ohmmeter and the output disconnected. Most of our pots and sensors are connectorized so they are easy to check and change.
As to using a scope, connect the scope lead common to the sensor common and the scope probe to the output lead. It should be obviously be in one state or the other. (set vertical sensitivity to 2v/division.) Move the part that is being sensed and the output should change states. If the output is always low, check that the sensor is getting power. If the output is always high, suspect that the sensor output is open.