View Enhancement Function: Defog

This function controls the heating defog grids on windshield, rear glass, and rear view mirrors.

1. Working Conditions

   The defog function can be activated only when engine is running and ignition key is in RUN position.

   • When windshield defog switch is pushed, windshield defog is activated for 20 minutes.
   • While windshield defog is on, the windshield defog button is illuminated
   • If the switch is pushed again while defog is already active, defog stops.
   • If the engine stops while defog is on, defog stops and it is NOT automatically turned on when the engine is started again
   • Rear defog works exactly in the same way as windshield defog using the rear defog switch button as input.
   • When rear defog is active, rear defog switch indicator is ON.
   • Rear defog ctrl output controls rear glass defog as well as rear view mirrors defog.
2. Rear defog pause
   • When IPM receives Tailgate Flasher CAN message, rear defog is inhibited for 30s
   • The 20min rear defog timer is frozen during this pause.
   • If the user turns on rear defog function while this pause is going on, Rear defog Ctrl is set to ON only at the end of the pause.
   • This pause has no impact on rear defog switch illumination.
   • When IPM receives Tailgate open CAN message transition to OPEN value, this 30 s rear defog pause is also started, it works the same way as described above.
   Fig 1: Rear Defog Flashing Pattern

   Courtesy of KIA MOTORS AMERICA, INC.
3. Functional Diagram
   Fig 2: Rear Defog Functional Diagram

   Courtesy of KIA MOTORS AMERICA, INC.