Owners of 2009 and later Volkswagen Jetta SportWagen models may note a lack of heat with the mode selection set on “Vent,” but enough heat with the mode set to “Floor.”
Check the G191 left vent temperature sensor for proper readings. Use MVB 5 field 1 for the vent temperature sensor reading and field 2 for the floor temperature sensor.
Move the heat selector to cold and see if the value change. The reading should be close to the outlet air temperature and will be displayed in Celsius.
The G191 sensor is located in the far left vent tube and can be accessed through the SC fuse panel cover.