THERMOSTAT OPERATION Table 2. This is the Main Display Figure 2. The Main Display 12 All information subject to change without notice. Copyright © 2016 DETROIT DIESEL CORPORATION DDC-SVC-MAN-0019 Up button Temperature in Fahrenheit indicator Down button Temperature in Celsius indicator Temperature bulb icon Cooling mode indicator Upper value icon Heating mode indicator Lower value icon Mode button Password mode icon for DDC distributors Cool/Heat selection button Temperature display Outside Temperature Parameter