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	Boot lid lamp, right Trailer module (AHM)

2	A	Left tail light	Tail light I left

3	A	Power supply E19 Right parking light	E19 Right parking light

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

7	M	Control unit ground	Ground point

8	A	Rear left turn signal indicator	Tail light I left

9	A	Left brake light	Tail light I left

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 Tyre pressure control	Front right auxiliary flasher unit

15	E	Voltage supply terminal 30	Fuse F106

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	Ground connector

3	A	Right low beam light	Low beam light, right

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

5	A	Signal, brake power-dependent brake light function (for USA only)	Tail light I left

6	A	Left high beam light	Left high beam

7	A	Left fog light	Left fog light

8	E	Voltage supply terminal 30	Fuse F107

9	A	Left reversing light	Boot lid lamp, left

10	A	Right reversing light	Boot lid lamp, right

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

12	A	Rear left turn signal indicator	Tail light I right

13	A	Signal, brake power-dependent brake light function (for USA only)	Tail light I right

14	A	Right brake light	Tail light I right

15	A	Left rear fog light	Boot lid lamp, left Trailer module (AHM)

Pin assignments at plug connector X10117

Pin	Type	Description / Signal type	Connection / Measuring notes
1	A	Lighting, light switch	S8 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	S8 Light switch

9	A	Automatic beam throw adjustment Supply, load/level sensor	Automatic beam throw adjustment Front right level sensor

10	E	Wash water level	Wash water level switch

11		Not used

12	E	Automatic beam throw adjustment Nominal value pick-up, load/level sensor	Automatic beam throw adjustment Front right level sensor

13	E	Voltage supply terminal R	Fuse F9

14		Not used

15	E	Oil level - thermal	DME control unit Digital diesel electronics control unit

16	E	Signal, night light dimmer	S8 Light switch

17	A	Right parking light	E47 Rear right light I

18	A	Left parking light	E15 Left parking light

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	H10 Gong

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

28	A	Reversing signal	Intermittent wipe/wash control unit, rear

29	A	5 V signal, potentiometer 1	S8 Light switch

30	E	Signal Turn signal indicator	Turn indicator/low beam selector

31	E	Terminal 15	Fuse F2

32		Not used

33	E	Headlights ON signal	Light switch

34	E	Signal Beam throw adjustment	Light switch

35	A	Interface AHM/LM	Trailer module (AHM)

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

37	M	Automatic beam throw adjustment Supply, load/level sensor	Automatic beam throw adjustment Rear right level sensor

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

42	A	Automatic beam throw adjustment Supply, load/level sensor	Automatic beam throw adjustment Rear right level sensor

43		Not used

44		Not used

45	E	Signal, rear fog light ON	Light switch

46		Not used

47	E	ABS/DSC indicator lamp	A65 ABS/DSC control unit

48		Not used

49	E	Automatic beam throw adjustment Nominal value pick-up, load/level sensor	Automatic beam throw adjustment Rear right level sensor

50	E	Signal High beam, headlight flasher switch	Turn indicator/low beam selector

51	E	Signal, parking light ON	Light switch

52	M	Electronic ground	Light switch

53	M	Automatic beam throw adjustment Supply, load/level sensor	Automatic beam throw adjustment Front right level sensor

54		Not used