all the cables from the trailer are connected to one of the rear tail light cluster. on the 7 pin plug there are numbers 1-7
no. Ref. Colour Fuction
1 L YELLOW Nearside Indicator
2 54G BLUE Rear Fog Lamps
3 31 WHITE Earth
4 R GREEN Offside Indicator
5 58R BROWN Offside Tail
6 54 RED Stop Lights
7 58L BLACK Nearside Tail & No. Plate
Hope this is some help to you. It Works for me and have done this many times. Bill
Bill, May 2006