Socket Pin Assignment
Pin
Circuit
1
Indicator lamp, left-hand side
2
Rear fog lamp
3
Ground (circuit 1-8)
4
Indicator lamp, right-hand side
5
Tail light, right-hand side
6
Stop lamp
7
Tail light, left-hand side
8
Back-up light
9
Constant plus
10
Charging line
11
Ground (circuit 10)
12
Trailer identification
13
Ground (circuit 9)
28
305 226 391 101 - 001 - 06/06
Installation instructions:
Electrical system for towing hitch
Wire Colour
black/white
gray/blue
brown/white
black/green
gray/red
black/red
gray/black
black/blue
red
--
--
--
brown
Audi A8