A21 Seat/steering column memory (SM/LSM) control unit

Plug connector overview

Number	X-pin, colour	Description
X650	12-pin, black	Plug connector Seat/steering column memory (SM/LSM) control unit
X653	4-pin, natural	Plug connector Seat/steering column memory (SM/LSM) control unit
X1465	15-pin, black	Plug connector Seat/steering column memory (SM/LSM) control unit
X18840	3-pin, black	Plug connector Seat/steering column memory (SM/LSM) control unit

Pin	Type	Description / Signal type	Connection / Measuring notes
1	E	Switch signal Steering column adjustment motor	Steering column adjustment motor

2	A	Positive activation Driver's backrest recliner motor	Driver's backrest recliner motor

3	A	Positive activation Driver's seat height adjustment motor	Driver's seat height adjustment motor

4	A	Positive activation Driver's seat cushion tilt motor	Driver's seat cushion tilt motor

5	A	Positive activation Driver's seat movement motor	Driver's seat movement motor

6	A	Positive activation Driver's back-rest actuator motor	Driver's back-rest actuator motor

7	A	Switch signal Steering column inclination motor	Steering column inclination motor

8	E	Negative activation Driver's backrest recliner motor	Driver's backrest recliner motor

9	E	Negative activation Driver's seat height adjustment motor	Driver's seat height adjustment motor

10	E	Negative activation Driver's seat cushion tilt motor	Driver's seat cushion tilt motor

11	E	Negative activation Driver's seat movement motor	Driver's seat movement motor

12	E	Negative activation Driver's headrest motor	Driver's headrest motor

Pin	Type	Description / Signal type	Connection / Measuring notes
1	E	Switch signal Steering column adjustment motor	Steering column adjustment switch

2	E	Switch signal Steering column adjustment motor	Steering column adjustment switch

3	E	Switch signal Steering column adjustment motor	Steering column adjustment switch

4	E	Switch signal Steering column adjustment motor	Steering column adjustment switch

Pin	Type	Description / Signal type	Connection / Measuring notes
1	A	Upward inclination signal Driver's seat	Driver's seat cushion tilt motor

2	A	Downward inclination signal Driver's seat	Driver's seat cushion tilt motor

3	A	Slide back signal Driver's seat	Driver's seat movement motor

4	A	Slide forward signal Driver's seat	Driver's seat movement motor

5	A	Signal, raise seat height Driver's seat	Driver's seat height adjustment motor

6	A	Ground	Ground point

7	A	Signal, seat backrest forward Driver's seat	Driver's backrest recliner motor

8	E	Pin assignments at plug connector 3	Fuse F26

9	E/A	I-bus connector	General module

10	A	Signal, lower seat height Driver's seat	Driver's seat height adjustment motor

11		Plug connector

12	A	Signal, raise head restraint Driver's seat	Driver's headrest motor

13		Plug connector

14	A	Signal, seat backrest back Driver's seat	Driver's backrest recliner motor

15	A	Signal, lower head restraint Driver's seat	Driver's headrest motor

Pin	Type	Description / Signal type	Connection / Measuring notes
1	M	Ground	Lumbar support switch, driver's seat

2		Not used

3	A	Voltage supply terminal 30	Lumbar support switch, driver's seat