i have just removed a westfalia detatchable towbar 7 pin from a salvage 5.0tdi v10 2004 and i am trying to fit it to my 2007 3.0tdi, all has gone well so far and i'm nearly done the only problem i have at the moment is the wires that go to the westfalia towtronic module.

i have 1 blue wire and 1 blue/red wire coming from the towtronic module and i know that i need to cut the grey/white wire that goes to the control unit on top of the o/s/r arch but i don't know which colour wire goes to which end of the grey/white wire.

also i have just noticed a green/brown wire which is taped in with the blue & blue/red, this green/brown wire goes to the 7 pin plug but it is not wired in, what is it used for.

on my 7 pin plug i have 9 wires ( white/black, white, blue, yellow, red, brown, green, black, green/brown) all are wired in apart from the above mentioned green/brown wire.

on my towbar there is a sticker with the following info:-
type 321490
charge 10013643
klasse a50-x
vw number 7L0 092 155

the towtronic module has the following numbers on it:- c1557

i have tried on the westfalia website but i can seem to find the info i need.

can anyone please help me