Arrived on site, homeowner stated she was seeing zone 2 sensor error on main thermostat. Upon inspection of the sensor, the display was active but the controls were unresponsive. From the main thermostat I could not access controls for zone 2. I then tested voltage at the zone board and measured 24 volts from R to C coming from the air handler to the zone board and to both damper controls. One damper was aprilaire and the other is a generic damper. Homeowner stated this generic damper was replaced under warranty shortly after installation 6 years ago when they moved in and the outdoor unit was installed. I was unable to properly test damper functionality as the second zone was not able to be controlled at this time. Zone board has 4 wires going to thermostat and sensor R/W/Bl/Bk. Voltages are as follows 4.7/R 27/W 13.3/Bl 13.3/Bk. Measured the same voltages across all 3 zone controller/sensor outputs on the zone board. This leads me to the conclusion that the sensor is bad at the very
