Rear seats control unit, component description - GF91.29-P-5250LE

MODEL 221.0 /1 as of model year 09/YoM 08 with CODE (223) Rear bench seat with electrically adjustable outer seats with PRE-SAFE positioning function for outer seats and outer head restraints 

MODEL 221.0 /1 as of model year 09/YoM 08 with CODE (872)) Electric seat heater for left and right rear seat 

MODEL 221.0 /1 as of model year 09 /YoM 08 with CODE (402) Rear deluxe seats, incl. seat heating and seat ventilation 

Illustrated on model 221.0 

Location 

The rear seats control unit is located behind the paneling in the luggage compartment on the right.

Task 

• Control of seat adjustment in rear as per the requests via the interior CAN (CAN B) (for code (223) Rear bench seat with electrically adjustable outer seats with PRE-SAFE positioning function for outer seats and outer head restraints)
• Saving the memory settings for the seats in the rear (for code (276) Memory in rear)
• Control of seat belt comfort-fit function (for code (223))
• Control of seat heater (for code (872) Electric seat heater for left and right rear seat or code (402) Rear comfort seats, including seat heater and seat ventilation)
• Control of seat ventilation (for code (402))
• Actuation of seat adjustment unit for PRE-SAFE (for code (223))
• Actuation of head restraint lowering mechanism in rear (for code (223))

These are grouped as follows:

• Reading in of sensors and signals 
• Evaluating input factors 
• Actuation of components 

Reading in of sensors and signals 

These input factors are read in via the following connections:

• Direct line 
• Interior CAN 

Direct line 

• Circuit 30
• Circuit 31

The following sensors (for code (223)) are read in via direct lines:

Hall sensors of;

• Left rear head restraint inclination adjustment motor (M18/15)
• Right rear head restraint inclination adjustment motor (M18/16)
• Left rear seat fore/aft adjustment motor (M18/17)
• Right rear seat fore/aft adjustment motor (M18/18)
• Left rear seat cushion inclination adjustment motor (M18/19)
• Right rear seat cushion inclination adjustment motor (M18/20)

Interior CAN 

• Terminal status from EIS [EZS] control unit (N73)
• Left rear seat operation switch group (S55/1) of left rear door control unit (N69/3)
• Right rear seat operation switch group (S55/2) of right rear door control unit (N69/4)
• PRE-SAFE request, status of emergency cutout of seat heater and seat ventilation due to low supply voltage and transmission selector lever position from central gateway control unit (N93)
• The status of the rear seat belt buckles from rear SAM control unit with fuse and relay module (N10/2)
• Signals for raising or lowering the head restraints in the rear from the central gateway control unit (N93) and from the left rear door control unit (N69/3) or from the right rear door control unit (N69/4) (for code 223)

Evaluating input factors 

The input factors read in are evaluated by the right front seat control unit, after which the actuators are actuated. The actuation of the motors for the seat adjustment takes place via integrated relays.

Actuation of components 

The actuation of the components takes place via the following connections:

• Direct line 
• Interior CAN 

Direct line 

The following components are actuated via direct lines:

• Left rear head restraint inclination adjustment motor (M18/15) (for code (223))
• Right rear head restraint inclination adjustment motor (M18/16) (for code (223))
• Left rear seat fore/aft adjustment motor (M18/17) (for code (223))
• Right rear seat fore/aft adjustment motor (M18/18) (for code (223))
• Left rear seat cushion inclination adjustment motor (M18/19) (for code (223))
• Right rear seat cushion inclination adjustment motor (M18/20) (for code (223))
• Left rear seat heated cushion (R13/5) (for code (872) or code (402))
• Left rear backrest heated cushion (R13/6) (for code (872) or code (402))
• Right rear seat heated cushion (R13/7) (for code (872) or code (402))
• Right rear backrest heated cushion (R13/8) (for code (872) or code (402))
• Left rear seat ventilation blower regulator (N29/3) (for code (402))
• Right rear seat ventilation blower regulator (N29/4) (for code (402))
• Seat belt comfort-fit solenoid, left rear (K18/6) (for code (223))
• Seat belt comfort-fit solenoid, right rear (K18/7) (for code (223))

Interior CAN 

• Signals for adjusting the stored pressures for the respective memory positions for the left rear multicontour backrest to the left rear multicontour backrest control unit (N32/20) (for code (406))
• Signals for adjusting the stored pressures for the respective memory positions for the right rear multicontour backrest to the right rear multicontour backrest control unit (N32/21) (for code (406))

Variants 

Min. variant 

• Without code (223)), with code (872)

Max. variant 

• With code (223) and with code (276) including seat belt comfort-fit, with code (872) and with code (402)

Wiring diagram of rear seat control unit

Control unit N25/6

PE91.29-P-2103-99SAA