I've been looking into getting a towing bracket for my Passat (1996 B4 estate). I've scanned in the fitting instructions for the three suppliers that I could find. Links are below.

Witter. To me (from the scans) this looks almost identical to the A1 bracket, and the A1 bracket is half the price. Click here to view gif. This towbar also fits the saloon (sedan). Witter can be contacted on 01244 341166 (UK number).

A1. Fits saloon or estate, B3 or B4, is cheap too. Get it from A1 Motorstores or similar. Does require a piece to be cut out of the rear bumper L . Click here to view gif.

York. This one's interesting; it only fits the estate, and has different mounting holes for a B3 or a B4. This kind of suggests that it will fit my B4 estate better. Still needs a piece to be cut from the rear bumper L and is quite expensive L too. The picture also shows an extra two mounting holes that the others don't have. The text however doesn't seem to suggest that any more are used than the others. At the moment I think I'll go for this one. Click here to view gif. Contact York on 01547 520690 (UK number).

Update

In the end the York towbar was too expensive and too difficult to get hold of, but as I wanted a known good quality towbar I bought the Witter. It fitted the car perfectly, but did require a hole to be cut in the rear plastic bumper. The towbar replaces the bumper mounting irons, and this is where one sees the difference. The bumper is normally bolted to the two bumper irons using four bolts. The York towbar appears to use all four bolts (which is I guess what limits it to the estate) whilst the Witter and A1 towbars use only two; this allows them to use spacers to mount the bumper of a saloon. This doesn't affect the strength of the towbar in any way, only the bumper, they all mount to the chassis in the same way, and now that I have seen how it works I am fairly happy with it, those two extra bolts are pretty redundant. The Witter towbar was certainly well made with neat welding and is pretty substantial looking. It is also slightly different to the picture above, and looks stronger to me for it.

What has taken much longer than fitting the bracket, is wiring the electrics to the 12N and 12S sockets, here are some tips:-

On a B4 Passat, the connections for both left and right indicators, left and right side lights, and brake lights are all available on the right hand side rear light cluster. It is not necessary to cut the factory wiring, all the connections are available as two amp spades on the bulb holder. One simply crimps a two amp spade on to the end of each cable going to the trailer lighting socket, and plug it in.

On the left hand side of the car, behind the side access door (at least on an estate) can be found several electric multi-plug connectors, these are:-

1. A five way connector but with only 3 or 4 used. One of these wires is an ignition switch live feed to the rear wash wipe. This is live whether the rear wiper is in use or not (it's for self parking). This is useful for triggering split charge and fridge relays (don't take a heavy current from it). The connection usefully goes dead when the starter motor is turning.

2. A two way connector with feed for reversing lights and rear fog lights.

3. A single way connector inline with the above two way one (can't remember whether it's upstream or downstream of it), which feeds just the fog lights. This is the point to break the circuit so that a fog light relay can be fitted.

There is a permanent, unswitched live feed at the back of the car, feeding the central locking pump, however I preferred not to touch this, so I ran a pair of new 20 amp cables from the battery, via a pair of fuses, to the back of the car.

In the UK at least it is mandatory to have either audible or visual indication that the trailer indicators are working, requiring some sort of relay.

My Passat was fitted with a flasher unit rated only for upto four indicator bulbs. With a trailer present, and the hazard warning lights in use, there are six bulbs. An uprated unit, or a slave relay is needed.

Using the mechanical switch on the 12N socket to kill the rear fog lights is rather poor. I would guess at the fog light circuit packing up after a few years; better to use a current sensing relay (mine only cost £7).

Older caravans took their aux charging feed from the relay on pin 2 of the 12S, however new caravans use this only is a signal, and actually take the current from pin 4. I used heavy gauge wiring for the circuits to both pin 2 and 4, so as to be compatible with old and new.

New caravans require a seperate fridge earth using pin 7 of the 12S, so earth both the white and the black 12S cables.

Click here to go to a site explaining the pin-outs of the UK 7 pin and European 13 pin electrical sockets.