Rear Head Restraint Adjustment, Function - GF91.16-P-0002LF
Model 217, 222
Shown on model 222 With Code 223 (Electrically adjustable rear bench seat)
Shown on model 222, Except Code 223 (Electrically adjustable rear bench seat), model 217.3
Shown on model 217.4
Function requirements, general
- Circuit 15R ON
- No overvoltage or undervoltage
- Head restraint adjustment normalized (model 222 with code 223 (Electrically adjustable rear bench seat), model 217.4)
The electronic ignition lock control unit sends the status of circuit 15 to the front SAM control unit via the interior CAN.
Lower rear head restraints
By lowering the rear head restraints, the driver can have a clear view through the rear window where required. With model 222 with code 223 (Electrically adjustable rear bench seat) or with model 217.4, the rear head restraints can also be raised again automatically.
The rear head restraints may be lowered using the following control points, depending on vehicle model and equipment:
- Rear head restraint button in the Audio/COMAND control panel (from model year 2018, Except Code 446 (Touchpad only) and except AMG vehicles (with engine 177, 279))
The Audio/COMAND control panel directly reads in the status of the rear head restraint button and sends this information via telematics CAN, COMAND controller unit or head unit, user interface CAN, electronic ignition lock control unit and interior CAN to the rear SAM control unit (except model 217.4), to the rear control unit (model 217.4) or to the rear seat control units (model 222 with code 223 (Electrically adjustable rear bench seat)).
- Rear head restraint button in lower control panel (from model year 2018 with code 446 (Touchpad only) and except AMG vehicles (with engine 177, 279))
The touchpad directly reads in the status of the rear head restraint button via UBF-LIN and sends this information via telematics CAN, COMAND controller unit or head unit, user interface CAN, electronic ignition lock control unit and interior CAN to the rear SAM control unit (except model 217.4), to the rear control unit (model 217.4) or to the rear seat control units (model 222 with code 223 (Electrically adjustable rear bench seat)).
- Rear head restraint button in the center instrument panel button group (up to model year 2018)
The front SAM control unit reads in the status of the rear head restraint button via the instrument panel LIN and sends this information via interior CAN to the rear SAM control unit (except model 217.4), to the rear control unit (model 217.4) or to the rear seat control units (model 222 with code 223 (Electrically adjustable rear bench seat)).
- Rear head restraint switch in the left front seat adjustment switch group (from model year 2018 AMG vehicles (with engine 177, 279))
The front door control unit reads in the status of the rear head restraint button via the front left door LIN and sends this information via interior CAN to the rear SAM control unit (except model 217.4), to the rear control unit (model 217.4) or to the rear seat control units (model 222 with code 223 (Electrically adjustable rear bench seat)).
Model 222 Except Code 223 (Electrically adjustable rear bench seat), model 217.3
The rear SAM control unit reads in the control request via the interior CAN and actuates the following components:
- Left rear passenger compartment head restraint release actuator
- Center rear head restraint release actuator (model 222)
- Right rear passenger compartment head restraint release actuator
The rear head restraints are lowered by their own weight. Once a function is actuated, a break of t = 3 s is maintained before the rear head restraint release actuator is actuated again.
The rear head restraints may only be raised again by hand.
Model 217.4
The rear control unit reads in the control request via the interior CAN and actuates the following components:
- Left rear seat head restraint height adjustment seat adjustment motor
- Right rear seat head restraint height adjustment seat adjustment motor
The rear head restraints are moved to the lowest position.
The seat adjustment motors are equipped with Hall sensors. The rear control unit evaluates the signals of the Hall sensors and saves the current position of the rear head restraints as the starting position.
Model 222 With Code 223 (Electrically adjustable rear bench seat)
The rear seat control units read in the control request via the interior CAN and actuate the following components:
- Left rear seat head restraint height adjustment seat adjustment motor
- Left rear seat head restraint inclination adjustment motor
- Center rear seat head restraint height adjustment motor (Right rear seat control unit)
The seat adjustment motors are equipped with Hall sensors. The rear seat control units evaluate the signals of the Hall sensors and save the current position of the rear head restraints as the starting position.
The rear head restraints are moved to the lowest position. The two outer rear head restraints are also inclined to the rear.
If the rear control unit or the rear seat control units register a repeat request, the outer rear head restraints are moved to the previously saved starting position. The center rear head restraints (model 222) may need to be manually adjusted.
For model 222 with code 223 (Electrically adjustable rear bench seat) or with model 217.4, the rear head restraints are raised again automatically when the seat belts are fastened.
Fastening of the seat belts is identified via the status of the respective rear belt buckle switch.
The rear SAM control unit reads in the rear belt buckle switch status directly and sends this information via the interior CAN to the rear seat control units (model 222 with code 223 (Electrically adjustable rear bench seat)) or to the rear control unit (model 217.4).
The rear seat control units (model 222 with code 223 (Electrically adjustable rear bench seat)) or the rear control unit (model 217.4) then actuates the corresponding seat adjustment motors in order to move the respective rear head restraints to the previously saved starting position.
Manually setting the rear head restraints (model 222 With Code 223 (Electrically adjustable rear bench seat))
The position of the respective rear head restraints can be manually adjusted via the rear seat head restraint adjustment switch and the center rear seat head restraint height adjustment switch.
Rear outer head restraints
The respective rear door control unit reads in the status of the rear seat head restraint adjustment switch via the door LIN, and sends the corresponding request via the interior CAN to the corresponding rear seat control unit.
The respective rear seat control unit actuates the following components according to the request:
- Rear seat head restraint height adjustment seat adjustment motor
- Rear seat head restraint inclination adjustment seat adjustment motor
Rear center head restraint
The rear right seat control unit reads in the status of the rear seat head restraint adjustment switch directly and correspondingly actuates the center rear seat head restraint height adjustment motor.
In order to make the adjustment, the relevant switch must be operated until the required position has been reached.
The position of the rear outer head restraints can be stored and called up again with the seat position using the memory function.
| Electrical function schematic for head restraint adjustment in rear | PE91.16-P-2053-97SEA | ||
| Overview of system components, electric seats | GF91.29-P-9992LF |