We have a code 50. The manual states that there is no communication from the tractor manager to the carriage manager. We have ordered and replaced the tractor manager. The console shows that there is no voltage in the battery. The battery has 49 volts (fully charged). When we attempt to follow the troubleshooting procedures in the manual, and perform analog test A00, the voltage displayed on the console is zero. We are at a loss on why the unit is still not showing the correct voltage on the display console, and all of the points that are supposed to have 48 volts when the battery is connected do not.