Remove and install air humidity sensor - AR83.40-P-6740V

MODELS 171.4 with CODE (580a) Automatic air conditioning 

Fig 1: Identifying Air Humidity Sensor Components

Courtesy of MERCEDES-BENZ USA

	Removal/installation
1	Open engine hood and raise to vertical position		AR88.40-P-1000V
2	Undo screws (2) in battery cover (1) and remove battery cover (1)
3	Rotate dew point sensor (B11/12) through 90° to the left and remove
4	Detach electrical connector from dew point sensor (B11/12)	Fasten electrical connector in place using adhesive tape, as otherwise it will fall into the AC housing.
5	Install in the reverse order
6.1	Read out fault memory	When replacing the dew point sensor (B11/12)
	Connect STAR DIAGNOSIS, read out fault memory		AD00.00-P-2000-04A
		Diagnosis system STAR DIAGNOSIS	*WH58.30-Z-1048-13A