JPC is right you CANNOT connect the towbar wiring to the VW loom without the specialist relay box, you will be in a world of pain, your trailer / number plate board will not be able to draw the current it requires from the std wiring loom, and they will fry the loom trying to. Warning lights will be the least of your problems, as will the beeper!
It actually makes installation easier anyhow, the only benefit of not going down this route would be to save a few quid for a solution that wouldn't work and then fried your loom - not good!
I took my live feed from the rear cigarette lighter which VW very conveniently sited in the rear compartment! Handy :-)
"Cannot"... CAN!! and i have and i've got no problems what so ever. I've travelled about 3000miles within the last couple of months with my trailer on the back and i've got absolutely no problems with it.
the plug is connected to the car wiring and the relay buzzer and thats it!
