Purpose of K1 and K2 Line

The instrument cluster is connected to the pushbutton control module of the air conditioning/air conditioning (automatic) via the K1 and K2 line.

The air conditioning pushbutton control module receives the following data from the instrument cluster via the serial data bus K1:
- Outside temperature
- Coolant temperature
- Vehicle speed
- Terminal 58d (illumination)
- Engine speed
- °F/°C changeover
- Full load shutoff (diesel engine)
- Acceleration recognition (gasoline engine)

Additionally as of 02.97:
- Compressor emergency off
- Compressor cut-out when accelerating
The instrument cluster receives the following data from the air conditioning pushbutton control module via the serial data bus K2:
- Refrigerant pressure
- Idle speed increase