A3 Light module

Plug connector overview

Number	X-pin, colour	Description
X12	15-pin, black	Plug connector Light module
X38	15-pin, white	Plug connector Light module
X10117	54-pin, black	Plug connector Light module

Pin assignments at plug connector X12

Pin	Type	Description / Signal type	Connection / Measuring notes
1	A	Right rear fog light	Rear right light I

2	A	Left tail light	Rear left light I

3	A	Right parking light	Right headlight EUR

3	A	Right front turn signal indicator	Right front turn signal indicator USA

4	A	Right fog light	Right fog light

5	A	Left licence plate light	Left licence plate light

6	A	Right front turn signal indicator	Right front turn signal indicator EUR

6		Not used	USA

7	M	Control unit ground	Ground point

8	A	Rear left turn signal indicator	Rear left light I

9	A	Left brake light	Rear left light I

10	A	Centre brake light	Raised brake light

11	A	Left low beam light	Low beam light, left

12	A	Right licence plate light	Right licence plate light

13	A	Right high beam light	Right high beam

14	A	Right front turn signal indicator	Front right auxiliary flasher unit

15	E	Voltage supply terminal 30	Fuse F6

Pin assignments at plug connector X38

Pin	Type	Description / Signal type	Connection / Measuring notes
1	A	Signal line, night lights	Connector terminal 58

2	M	Control unit ground	Clutch signal

3	A	Right low beam light	Low beam light, right

4	A	Left front turn signal indicator	Front left auxiliary flasher unit

5	A	Inner left tail light	Rear left light I

6	A	Left high beam light	Left high beam

7	A	Left fog light	Left fog light

8	E	Voltage supply terminal 30	Fuse F113

9	A	Left reversing light	Rear left light I

10	A	Right reversing light	Rear right light I

11	A	Left front turn signal indicator	Left front turn signal indicator

12	A	Rear left turn signal indicator	Rear right light I

13	A	Inner right tail light	Rear right light I

14	A	Right brake light	Rear right light I

15	A	Left rear fog light	Rear left light I

Pin assignments at plug connector X10117

Pin	Type	Description / Signal type	Connection / Measuring notes
1	A	Lighting, light switch	Light switch

2	A	Signal, headlight vertical aim control	Actuator for headlight beam throw control, left

3	A	Signal, headlight vertical aim control	Actuator for headlight beam throw control, left

4	A	Signal, headlight vertical aim control	Actuator for headlight beam throw control, left

5	A	Signal, headlight vertical aim control	Actuator for headlight beam throw control, left

6		Not used

7	E	Signal, hazard warning lights ON	Hazard warning flasher switch

8	E	Signal, rear fog light ON	Fog light switch

9		Not used

10	E	Wash water level	Wash water level switch

11		Not used

12	A	Warning lamp preheating/error signal	DDE control unit (M51 only)

13	E	Voltage supply terminal R	Fuse F44

14		Not used

15	E	Oil level - thermal	DME control unit Digital diesel electronics control unit (not M51)

16	E	Signal, night light dimmer	Dimmer

17	A	Right tail light	Rear right light I

18	A	Left parking light	Left headlight EUR

18	A	Left front turn signal indicator	Left front turn signal indicator USA

19	A	Lights, hazard warning switch	Hazard warning flasher switch

20	A	Signal, headlight vertical aim control	Actuator for headlight beam throw control, right

21	A	Signal, headlight vertical aim control	Actuator for headlight beam throw control, right

22	A	Signal, headlight vertical aim control	Actuator for headlight beam throw control, right

23	A	Signal, headlight vertical aim control	Actuator for headlight beam throw control, right

24	E	Coolant level	Coolant level switch

25	E	Brake light signal	Brake light switch

26	A	Reversing signal	Gong Japan

27	A	Supply for beam throw control unit (LWR)	Beam throw adjustment control unit (LWR)

28		Not used

29		Not used

30	E	Signal, right turn signal indicator	Turn indicator/low beam selector

31	E	Terminal 15	Fuse F23

32		Not used

33	E	Headlights ON signal	Light switch

34	E	Signal Beam throw adjustment	Headlight beam angle adjust potentiometer

35	E	Interface for eject box/interface/transceiver	Trailer module (AHM) EUR

36	E/A	I/K-bus signal link	Connector, I/K-bus

37		Not used

38	E	Reversing signal	Navigation control unit

39	E	Reversing signal	Electrochromic interior rear view mirror

40		Not used

41	E	Brake fluid level	Brake fluid level switch ABS/DSC control unit

42		Not used

43		Not used

44		Not used

45	E	Signal, rear fog light ON	Fog light switch

46		Not used

47	A	Signal, brake light	ABS/DSC control unit

48		Not used

49		Not used

50	E	Signal, high beam ON	Turn indicator/low beam selector

51	E	Signal, parking light ON	Light switch

52		Not used

53	E	Signal Beam throw adjustment	Headlight beam angle adjust potentiometer

54	A	Lights, terminal 58	EDC control unit