Front SAM Control Unit, Component Description - GF54.21-P-7030RF

Model 205, 253 

Shown on model 205.0 up to 31.05.2018 

Courtesy of MERCEDES-BENZ USA

Location 

The rear SAM control unit is located in the right of the trunk beneath the cover.

Tasks 

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

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

Reading in of sensors and signals 

The input factors are read in via the following connections:

• Direct line 
• Heater LIN (LIN B28) 
• Interior CAN (CAN B) 

Direct line 

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

• Trunk lid/liftgate lock main lock switch (A85/5s1)
• Trunk lid/liftgate lock safety catch switch (A85/5s2) (model 205.2, 253)
• Reverse switch for liftgate lock element (M14/4) (model 205.2 up to 31.05.2018, 253 (except for model 253.99) up to 31.05.2019 with code 890 (EASY-PACK liftgate))
• Left load compartment cover Hall sensor (M50/1b1) (model 205.2, 253 with CODE 890 (EASY-PACK liftgate))
• Right load compartment cover Hall sensor (M50/2b1) (model 205.2, 253 with CODE 890 (EASY-PACK liftgate))
• Electronic Stability Program control unit (N30/4) (circuit 54)
• Right rear brake wear sensor (S10/4)
• Left rear seat backrest inclination switch (S54/5) (model 205.0/1/2/3, 253 with code 287 (Folding seat backrests in rear passenger compartment) or model 205.4)
• Right rear seat backrest inclination switch (S54/6) (model 205.0/1/2/3, 253 with code 287 (Folding seat backrests in rear passenger compartment) or model 205.4)
• Left rear backrest lock switch (S54/7) (model 205.0/1/3 with code 287 (Folding seat backrests in rear passenger compartment))
• Right rear backrest lock switch (S54/8) (model 205.0/1/3 with code 287 (Folding seat backrests in rear passenger compartment))
• Left trunk rear backrest release button (S54/9) (model 205.2/4, 253)
• Right trunk rear backrest release button (S54/10) (model 205.2/4, 253)
• Left rear backrest release button (S54/11) (model 205.2, 253)
• Right rear backrest release button (S54/12) (model 205.2, 253)
• Trunk lid/liftgate control button (S62/26) (model 205.0/1/3/4 with CODE 881 (Remote trunk closing), model 205.2, 253 with CODE 890 (EASY-PACK liftgate))
• Left rear seat belt buckle switch (S68/11)
• Right rear belt buckle switch (S68/12)
• Center rear seat belt buckle switch (S68/14) (model 205.0/1/2, 253)
• Trunk lid/liftgate external operation switch (S88/8)
• Trunk lid emergency opening switch (S88/10) (model 205.0/1/3/4 with CODE 494 (USA version))
• Left seat backrest release microswitch (S91/6s1) (model 205.3/4 except code P65 (Seat Comfort Package))
• Right seat backrest release microswitch (S92/6s1) (model 205.3/4 except code P65 (Seat Comfort Package))
• Rear camera cover motor switch (M35/2s1) (model 205 as of 01.06.2018, model 253 (except model 253.99) as of 01.06.2019, model 253.99, with code 218 (reversing camera) or code 501 (360° camera))

Heater LIN 

The signals are read in by the rear SAM control unit via the heater LIN. The functions that use these signals are described in the individual function descriptions (see block diagram or function schematic).

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 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:

• Ambient lighting in rear (model 205 up to 31.05.2018, model 253 (except model 253.99) up to 31.05.2019, with code 876 (Interior Light Package))
• Central locking
• Trunk lid/liftgate power closing (model 205.0/1/3/4 with code 881 (Remote trunk closing), model 205.2, 253 with code 890 (EASY-PACK liftgate))

Actuation of components 

The following components are actuated via direct lines:

• Trunk lid/liftgate lock motor (A85/5m1)
• Left rear lamp unit (E3):
  • Left rear turn signal light (E3e1) (except code 460 (Canada version) and except code 494 (USA version), model 253.3 as of 01.06.2019)
  • Left backup lamp (E3e3) (model 205.0/1, model 253 (except model 253.99) as of 01.06.2019)
  • Left backup lamp (E3/1e3) (model 205.2/3/4, 253 up to 31.05.2019)
  • Left brake light (E3e4)
  • Left rear fog light (E3e5) (model 205.0/1)
  • Left rear fog light (E3/1e5) (model 205.2/3/4, 253)
  • Left side marker lamp (E3e6) (with code 460 (Canada version) or code 494 (USA version), except model 253 as of 01.06.2019)
  • Outer left taillight (E3e16) (model 205.3/4, 253.3)
  • Left taillight (E3e18) (model 205.0/1/2, 253.9)
  • Upper left brake light (E3e23) (model 205.0/1 as of 01.06.2018, with LED headlamp)
  • Outer lower left brake light (E3e30) (model 205.0/1 as of 01.06.2018, with LED headlamp)
  • Inner lower left brake light (E3e31) (model 205.0/1 as of 01.06.2018, with LED headlamp)
• Right rear lamp unit (E4):
  • Right rear turn signal light (E4e1) (except code 460 (Canada version) and except code 494 (USA version), model 253.3 as of 01.06.2019)
  • Right rear turn signal light (E4e3) (model 205.0/1, model 253 (except model 253.99) as of 01.06.2019)
  • Right rear turn signal light (E4/1e3) (model 205.2/3/4, 253 up to 31.05.2019)
  • Right brake light (E4e4)
  • Right side marker lamp (E4e6) (with code 460 (Canada version) or code 494 (USA version), except model 253 as of 01.06.2019)
  • Outer right taillight (E4e16) (model 205.3/4, 253.3)
  • Right taillight (E4e18) (model 205.0/1/2, 253.9)
  • Upper right brake light (E4e23) (model 205.0/1 as of 01.06.2018, with LED headlamp)
  • Outer lower right brake light (E4e30) (model 205.0/1 as of 01.06.2018, with LED headlamp)
  • Inner lower right brake light (E4e31) (model 205.0/1 as of 01.06.2018, with LED headlamp)
• Right trunk lamp (E18/4)
• Left trunk lamp (E18/5) (model 205.2, 253)
• 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)
• Right trunk lid/liftgate ambient lamp and warning lamp (E40/3) (model 205.2, 253)
• Liftgate wiper motor (M6/4) (model 205.2, 253)
• Trunk lid lock element (M14/31) (model 205.0/1/3/4 with CODE 881 (Remote trunk closing))
• Liftgate lock element (model 205.2, 253 with CODE 890 (EASY-PACK liftgate))
• Tank cap central locking actuator (M14/10)
• Stowage compartment central locking actuator motor (M14/19) (model 205.4)
• Rear window roller sun blind motor (M24) (model 205.0/1 with CODE 540 (Electric roller sun blind for rear window))
• Left load compartment cover actuator motor (M50/1) (model 205.2, 253 with CODE 890 (EASY-PACK liftgate))
• Right load compartment cover actuator motor (M50/2) (model 205.2, 253 with CODE 890 (EASY-PACK liftgate))
• Left rear seat backrest release actuator (M53/15) (model 205.2, 253 with code 287 (Folding seat backrests in rear passenger compartment) or model 205.4)
• Right rear seat backrest release actuator (M53/16) (model 205.2, 253 with code 287 (Folding seat backrests in rear passenger compartment) or model 205.4)
• Left rear footwell lamp (E17/17) and right rear footwell lamp (E17/18) (model 205.1 as of 01.06.2018 except for code 877 (ambient lighting))
• Ambiance illumination power supply (with CODE 877 (Ambiance illumination))
• Rear camera cover motor (M35/2) (model 205 as of 01.06.2018, model 253 (except model 253.99) as of 01.06.2019, model 253.99, with code 218 (reversing camera) or code 501 (360° camera))

Sending signals 

The rear SAM control unit sends signals via the following connections:

• Heater LIN 
• Interior CAN 

Heater LIN 

The signals are sent by the rear SAM control unit via the heater LIN. The functions that use these signals are described in the individual function descriptions (see block diagram or function schematic).

Interior CAN 

The signals are sent by the rear SAM control unit via the interior CAN. The functions that use these signals are described in the individual function descriptions (see block diagram or function schematic).

Switching of relays 

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

• Vehicle interior circuit 15 relay (K40/5kS) (model 205 up to 31.05.2018, model 253 (except model 253.99) up to 31.05.2019)
• Rear window heater relay (K40/5kT)
• 2nd seat row cup holder and sockets relay (K40/5kU)
• 1st seat row/trunk refrigerator box and sockets relay (K40/5kX)

	Wiring diagram for rear signal acquisition and actuation module (SAM) control unit	Model 205 as of model year 2019	PE54.21-P-2103-97FBB
		Model 253 (except 253.99) as of model year 2020Model 253.99	PE54.21-P-2103-97FCA
		Model 205 up to model year 2019Model 253 (except 253.99) up to model year 2020	PE54.21-P-2103-97FBA