Battery Voltage: The scan tool displays the current state of the battery in volts.
Horn Relay: The scan tool displays the commanded state of the horn relay. The
scan tool displays ON when the BCM applies ground to the horn relay to activate
   the horn(s).
Horn Relay Input: The scan tool displays the state of the horn relay. The scan tool
displays ACTIVE when the BCM senses that the horn relay is being commanded
        ON by the relay coil circuit being grounded.