I dropped the center trim piece from the headliner today to get to the motor and switch so I could troubleshoot.
When disengaged from the sunroof the motor would turn one direction, but not the other so clearly my issue was either a bad switch or a bad motor/transmission unit. Since I get nothing when the motor was installed, I suspected it, or the gears. Fortunately the cover comes off the drive gear easily and revealed the problem. A broken plastic gear.
New one on order.