I have made a balls up purchasing the towbar loom for my A3, It wasn't untill I had threaded the loom from the back of the car to the front up behind the fuse box and connected everything apart from one plug that I couldn't find a home for, It said in the instructions to connect it to the brake switch above the brake pedal - to which I couldn't find, my stomach then started turning as I saw on the front of the booklet "not suitable for cars without brake switch!" bugger
On the loom I have, the connecter is 4 pin (3 white and 1 red/black). For this loom you would unplug the plug from the brake light switch, plug it into the towbar loom then plug the towbar loom back onto the brake switch.
Is there any way I can adopt this "incorrect" loom to fit my car? Think my brake light switch is on my master cylinder under the bonnet but the wires are different colours.