A3 Light module

Plug connector overview

Number	X-pin	Description
X12	15	Light module Plug connector A
X38	15	Light module Plug connector B
X10117	54	Light module Plug connector C

Pin assignments at plug connector A 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	Front right parking light	Right headlight

4	A	Right fog light	Right fog light

5	A	Left licence plate light	Left licence plate light

6	A	Front right turn indicator	Front right turn indicator

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	Left headlight

12	A	Right licence plate light	Right licence plate light

13	A	Right high beam light	Right headlight

14	A	Front right turn indicator	Front right auxiliary flasher unit

15	E	Terminal 30	Fuse F6

Pin assignments at plug connector B X38

Pin	Type	Description / Signal type	Connection / Measuring notes
1	A	Night light signal	Connector, terminal 58g

2	M	Control unit ground	Ground connector

3	A	Right low beam light	Right headlight

4	A	Front left turn indicator	Front left auxiliary flasher unit

5	A	Inner left tail light	Rear left light I

6	A	Left high beam light	Left headlight

7	A	Left fog light	Left fog light

8	E	Terminal 30	Fuse F2

9	A	Left reversing light	Rear left light I

10	A	Right reversing light	Rear right light I

11	A	Front left turn indicator	Front left turn 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 C X10117

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

2	A	Activation - left-hand adjustment	Left headlight

3	A	Motor ground - left-hand adjustment	Left headlight

4	A	Activation - left-hand adjustment	Left headlight

5	A	Motor ground - left-hand adjustment	Left headlight

6	E	Belt signal	Driver's seat belt buckle switch

7	E	Signal, hazard warning lights ON	Hazard warning 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 DDE

13	E	Terminal R	Fuse F41

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

15	E	Oil level - thermal	Oil level sensor

16	E	Signal, night light dimmer	Dimmer

17	A	Inner right tail light	Rear right light I

18	A	Front left parking light	Left headlight Front left turn indicator US

19	A	Lights, hazard warning switch	Hazard warning switch

20	A	Activation - right-hand adjustment	Left headlight

21	A	Motor ground - right-hand adjustment	Left headlight

22	A	Activation - right-hand adjustment	Left headlight

23	A	Motor ground - right-hand adjustment	Left headlight

24	E	Coolant level	Coolant level switch

25	E	Brake light signal	Brake light switch

26	A	Acoustic 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		Not used

31	E	Terminal 15	Fuse F16

32	E	Signal, left turn signal indicator	Turn indicator/low beam selector

33	E	Headlights ON signal	Light switch

34	E	Signal Beam throw adjustment	Headlight beam angle adjust potentiometer

35	E	AHM signal line	Rear right light I

36	E	I-bus signal line	I-bus connector

37		Not used

38	E	Not used

39	A	Activation, interior rear-view mirror	Electrochromic interior rear view mirror

40		Not used

41	E	Brake fluid level	Brake fluid level switch

42	E	Ignition key warning (US only)	Ignition switch

43	E	Headlamp flasher signal	Turn indicator/low beam selector

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

45	E	Signal, rear fog light ON	Fog light switch

46		Not used

47		Not used

48		Not used

49	E	Catalytic converter overheated	Thermal switch (LA Japan)

50		Not used

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