Mercedes-Benz ML320. Manual — part 228

How it works

An infrared transmitter (2)sends infrared light to a lens (1) which directs the beam to the windshield (4) . The
intensity of the light reflected by the windshield is measured by an IR receiver (3)located at the opposite end of
the lens.



Dry windshield (Fig. A)

When the area around the rain sensor (B38) is dry nearly all of the light is reflected and the IR receiver
(3) measures a high level of light intensity.



Wet windshield (Fig. B)

When the reflection area is wet, some of the light is scattered away from the glass of the windshield. This
reduces the intensity of the reflected light and the IR receiver (3) measures a lower level of light intensity.

The light intensity measured by the IR receiver (3) provides a measure of the rain intensity on the windshield.
Lower light intensities indicate higher levels of rain intensity on the windshield.

Fig. 26: Identifying Infrared Transmitter And IR Receiver

Rain sensor data flow

The rain sensor (B38) networks with the All Activity Module (AAM, N10) via the engine compartment CAN.

More than just a "rain sensor," the unit also comprises integrated light sensors for the vehicle lighting

2001 Mercedes-Benz ML320

1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis

me

system . Data from the light sensors is also sent to the All Activity Module (AAM, N10) via the engine
compartment CAN.

Power supply

Power is supplied to the rain sensor (B38) via KI. 15 so that these functions are available only when the ignition
is on.

RAIN SENSOR - LOCATION/TASK/DESIGN/FUNCTION - GF82.30-P-4103GH

MODEL 163 with code 345a Rain sensor

Fig. 27: Identifying Rain Sensor Location

Rain Sensor - Location

The rain sensor (B38) is
adhered to the inside
surface of the windshield.

Rain Sensor - Task

The rain sensor (B38)
assesses the rain
intensity on the
windshield and
automatically adjusts the
intermittent wiper speed.
In addition, light sensors
gauge ambient light

2001 Mercedes-Benz ML320

1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis

me

WIPER MOTOR, FUNCTION - GF82.30-P-4104-01GH

The wiper arm can be driven by the motor with two speeds. The motor runs at high or low speed depending on
brush voltage present.

The cam switch switches circuit 31b from circuit 15 to circuit 31 when the windshield wiper runs through the
park position.

WIPER MOTOR, DESIGN - GF82.30-P-4104-02GH

The windshield wiper is driven by the wiper motor (M6/1) , an electric motor with three brushes and gear. The
cam switch is located on the output shaft.

Fig. 28: Identifying Wiper Motor

WIPER MOTOR, LOCATION/PURPOSE/DESIGN/FUNCTION - GF82.30-P-4104GH

MODEL 163

conditions and this data
is used to control the
vehicle's light system.

Rain Sensor - Design

The rain sensor (B38)
comprises an IR
transmitter and receiver
unit, light sensors and an
electronic data analysis
and interface circuit. The
rain sensor (B38) is
connected to the engine
compartment CAN .

Rain Sensor - Function

GF82.30-P-4103-02GH

2001 Mercedes-Benz ML320

1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis

me

REAR WIPER/WASHER SWITCH - FUNCTION - GF82.30-P-4105-01GH

The rear intermittent wipe function is started by placing the rear wiper/washer switch (S78) in the up position.
The switching contact connects the input (c) to the All Activity Module (AAM, N10) to terminal 15 (a).

The rear wash function is started by placing the switch in the down position. Power is fed to the tailgate
washer pump (M5/3) (b) from terminal 15 via the second switch contact and the AAM input (c) is
simultaneously connected to terminal 15 via the resistor (R).

As of 1.9.2000:

When the rear intermittent wipe function is activated manually the LED built into the rear wiper/ washer switch
(S78) will illuminate. LED illumination is controlled by the All Activity Module (AAM, N10) .

Fig. 29: Identifying Rear Wiper/Washer Switch Function

REAR WIPER/WASHER SWITCH - LOCATION/TASK/DESIGN/FUNCTION - GF82.30-P-4105GH

MODEL 163

Wiper motor, location

GF82.30-P-0005-01GH

Wiper motor, purpose

Wiper motor drive for
windshield.

Wiper motor, design

GF82.30-P-4104-02GH

Wiper motor, function

GF82.30-P-4104-01GH

Location

GF82.30-P-0004-01GH

Task

To control the rear
intermittent wipe and rear
wash functions
Starting 1.9.2000 this
switch will also include
an ON/OFF indicator
LED for the rear wiper.

Design

The rear wiper switch
consists of a push-button

2001 Mercedes-Benz ML320

1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis

me