Component Description For Rear Sam Control Unit - GF54.21-P-7030FR

Model 257, 290 up to model year 2021

Fig 1: Rear Sam Control Unit Component Location - Model 257 Up To Model Year 2021

Courtesy of MERCEDES-BENZ USA

Shown on model 257

Location

The rear SAM control unit is on the right in the trunk behind the cover.

Tasks

Depending on the function sequence, the rear SAM control unit supplies voltage to various systems and control units via limit switches. In addition, the rear SAM control unit has the following tasks:

Reading in of signals
Evaluation of input factors
Controlling functions
Actuation of components
Switching of relays
Sending signals

Reading in of signals

The input factors are read in via the following connections:

Direct line
Interior CAN (CAN B)

Direct line

The signals from the following components are read via direct lines:

Trunk lid lock main catch switch (A85/5s1)
Trunk lid/liftgate lock safety catch switch (A85/5s2) (with code 883 (Power closing))
Tank cap central locking actuator (M14/10)
Reverse switch for trunk lid/liftgate lock element (M14/31) (Code 881 (Remote trunk closing))
Rear window roller sun blind motor Hall sensor (M24) (with code 540 (Electric roller sun blind for rear window))
Rear camera cover motor switch (M35/2s1) (with code 218 (Reversing camera) or code 235 (Parking Pilot with PARKTRONIC) or code P44 (Parking Package))
Electronic Stability Program control unit (N30/4) (circuit 54)
Right rear brake wear sensor (S10/4)
Left rear backrest inclination switch (S54/5)
Right rear backrest inclination switch (S54/6)
Left rear backrest lock switch (S54/7)
Right rear backrest lock switch (S54/8)
Trunk lid/liftgate control button (S62/26) (with code 881 (Remote trunk closing))
Left rear seat belt buckle switch (S68/11)
Right rear belt buckle switch (S68/12)
Center rear seat belt buckle switch (S68/14)
Trunk lid/liftgate external operation switch (S88/8)
Trunk lid emergency opening switch (S88/10) (with code 460 (Canada version) or code 494 (USA version))

Interior CAN

The signals are read in by the rear SAM control unit via the interior CAN.

The functions that use these signals are described in the individual function descriptions (see the appropriate block diagram or function schematic).

Evaluation of input factors

The input factors are evaluated by the microprocessor and the corresponding components are actuated.

Controlling functions

The rear SAM control unit controls the following functions:

Central locking
Front seat heater (with code 401 (Seat climate control for driver and front passenger), code 873 (Seat heater for driver and front passenger) or code 902 (Seat heater Plus for driver and front passenger))
Rear seat heater (with code 872 (Seat heater in rear))
Front seat ventilation (with code 401 (Seat climate control for driver and front passenger))
Trunk lid/liftgate power closing (with code 883 (Power closing)) Actuation of components
The following components are actuated via direct lines:
Trunk lid lock motor (A85/5m1)
Left rear lamp unit (E3)
Right rear lamp unit (E4)
Trunk lamp (E18/1)
Left license plate lamp (E19/1)
Right license plate lamp (E19/2)
Center brake lamp (E21)
Left trunk lid/liftgate ambient lamp and warning lamp (E40/2)
Tank cap central locking actuator
Trunk lid/liftgate lock element (with code 881 (Remote trunk closing))
Rear window roller sun blind motor (with code 540 (Electric roller sun blind for rear window))
Rear camera cover motor (M35/2) (with code 218 (Reversing camera) or code 235 (Parking Pilot with PARKTRONIC) or code P44 (Parking Package))

The rear SAM control unit additionally supplies voltage to the comfort switch and controls illumination, switch illumination (circuit 58d) and ambiance illumination (with code 877 (Ambiance illumination)).

Switching of relays

The following relays are switched by the rear SAM control unit:

Rear window heater relay (K40/5kT)

Sending signals

The signals are sent by the rear SAM control unit over the interior CAN.

The functions that use these signals are described in the individual function descriptions (see the appropriate block diagram or function schematic).

Wiring diagram of rear signal acquisition and actuation module (SAM) control unit

PE54.21-P-2103-97XBA