Component Description For Driver Seat Control Unit - GF91.29-P-5231FH

Model 238 

Up To Model Year 2021 

With Code 275 (Memory Package (driver's seat, steering column and mirror)) 

The component description for the driver seat control unit (N32/1) describes a left-hand drive vehicle. Right-hand drive vehicles are to be observed mirror inverted with regard to the designations of the electric components.

Courtesy of MERCEDES-BENZ USA

Location 

The driver seat control unit is located at the bottom of the driver seat frame.

Task 

The driver seat control unit is responsible for the following tasks:

• Control of seat adjustment
• Control of steering column adjustment
• Storing/moving to memory settings for seat and steering column
• Control of easy entry/exit
• Control of crash-active easy exit
• Controlling the collision avoidance feature

The tasks are subdivided as follows:

• Read in sensors and signals 
• Evaluation of input factors 
• Actuation of components 
• Transmitting signals 

Read in sensors and signals 

The input factors are read in via the following connections:

• Direct line 
• Interior CAN (CAN B) 

Direct line 

The driver seat control unit reads in the signals from the following sensors over direct lines:

• Steering column in/out Hall sensor (M20/1b1)
• Steering column up/down Hall sensor (M20/2b1)
• Seat fore/aft adjustment Hall sensor, driver seat (M27/1b1)
• Head restraint adjustment Hall sensor, driver seat (M27/4b1)
• Backrest inclination Hall sensor, driver seat (M27/5b1)
• Seat cushion length adjustment Hall sensor, driver seat (M27/8b1)
• Seat inclination adjustment Hall sensor, driver seat (M27/9b1)
• Seat height adjustment Hall sensor, driver seat (M27/10b1)
• Left backrest release microswitch (S91/6s1) in left backrest release/backrest inclination microswitch (S91/6)
• Left backrest inclination microswitch (S91/6s2) in left backrest release/backrest inclination microswitch

With code 902 (Seat heater plus for driver and front passenger):

• Left front seat cushion side bolster heater pad temperature sensor(R13/11b1)
• Left front seat backrest side bolster heater pad temperature sensor (R13/12b1)

Interior CAN 

The driver seat control unit reads in the following signals via interior CAN, among other things:

• Seat adjustment request
• Steering column adjustment request
• Request for storing/moving to memory position
• Status of backrest in rear

Evaluation of input factors 

The read in input factors are evaluated by the driver seat control unit. The motors for seat and steering column adjustment are actuated via integrated relays.

Actuation of components 

The driver seat control unit actuates the following components via direct lines:

• Left front seat cushion seat ventilation motors (M18/9) (with CODE 401 (Seat climate control for driver and front passenger))
• Left front backrest seat ventilation motors (M18/10) (with CODE 401 (Seat climate control for driver and front passenger))
• Steering column in/out adjustment motor (M20/1)
• Steering column up/down adjustment motor (M20/2)
• Driver seat fore/aft adjustment motor (M27/1)
• Driver seat head restraint adjustment motor (M27/4)
• Driver seat backrest inclination adjustment motor (M27/5)
• Driver seat cushion length adjustment motor (M27/8)
• Driver seat inclination adjustment motor (M27/9)
• Driver seat height adjustment motor (M27/10)
• Left front seat cushion heater pad (R13/1) (with code 401 (Seat climate control for driver and front passenger) or code 873 (Seat heater for driver and front passenger))
• Left front seat backrest heater pad (R13/2) (with code 401 (Seat climate control for driver and front passenger) or code 873 (Seat heater for driver and front passenger))
• Left front seat cushion seat side bolster heater pad (R13/11) (with code 902 (Seat heater plus for driver and front passenger))
• Left front seat backrest seat side bolster heater pad (R13/12) (with code 902 (Seat heater plus for driver and front passenger))
• Left front seat heater pad for adjustable seat cushion length (R24) (with code 401 (Seat climate control for driver and front passenger) or code 873 (Seat heater for driver and front passenger) or code 902 (Seat heater plus for driver and front passenger))

Transmitting signals 

The driver seat control unit sends signals via the following connections:

• Seat LIN, driver (LIN B18) (With Code 902 (Seat heater plus for driver and front passenger)) 
• Interior CAN 

Seat LIN, driver (With Code 902 (Seat heater plus for driver and front passenger)) 

The driver seat control unit transmits, among other things, the "Switch on seat heater" request via the driver seat LIN to the driver seat heater control unit (N25/5).

Interior CAN 

The driver seat control unit sends the following signals via interior CAN, among other things:

• Request for acknowledge tone after storage in memory
• Request for storing/occupying memory position
• Seat ventilation status (with CODE 401 (Seat climate control for driver and front passenger))
• Seat heater status (with code 401 (Seat climate control for driver and front passenger) or code 873 (Seat heater for driver and front passenger) or code 902 (Seat heater plus for driver and front passenger))

Variants 

There are no variants for the hardware of the driver seat control unit. The country or left-hand drive vehicle/right hand drive vehicle allocation is software coded.

Wiring diagram of driver seat control unit

PE91.29-P-2104-97DCA