Rewiring Lights on our VW Camper Vans for UK use

The challenge of how to make a US spec bus pass a UK MOT that requires seperate flashing indicators of orange or amber colour.

This is a typical 67 spec wiring diagram (click to get the big picture – curtesy www.type2.com);

Its important to realise that the brake lights are the oddity here on US buses – the indicators are fine since they flash correctly when the brakes are not being pressed. The plan is to modify (or simplify) how the brake lights work and to remove their inter-action with the indicators.

Starting at the brake light switch, the pressure switch is a simple device – at around 15 psi or so the contacts should close. So if one side is ‘hot’ (actually switched with ignition so not always hot) then the other side only gets a voltage when there is pressure in the switch.. This is the brake light switch (J1)

Notice the black/red striped wires – one side comes from the fusebox and the other goes to the 9 pin relay. In the wiring for a split screen is the famous 9 pin relay which does the job of combining the brake lights indicators and emergency flashers into one box (its internal layout is non trivial btw). The brake light wire goes to terminal 54 – visible on the bottom left of the relay (J) in this picture;

The black/red wire needs to come off that relay and go to the back of the car to connect to the brake lights. So we need to re-assign a wire that goes from the front of the bus to the back. At the fusebox we can see that there are two wires that run from the fusebox to the rear of the bus that do the job of sidelights – circled here;

Notice the two grey coloured wires – grey/black stripe and grey/red stripe. We can imagine that VW would prefer 2 seperate runs of wire for the rear lights in case one blows a fuse you still have one light. But anyway there are two  0.75mm sq (20 awg) wire to the function of powering the rear side lights (15W max) which is overkill. This is where they go at the rear light wiring;

So we’ll use one of those rear light cables for the new brake lights – the grey/black is a single run from the fusebox to the left side side light. Disconnect this from the fusebox terminal and re-connect it to the black/red wire that used to be connected to terminal 54 of the 9 pin relay. Insulate the connector. We’re done at the front of the bus.

At the back of the buse the grey/red side light wiring will need to be extended from the right side light housing to the left side. Whilst this is being done we ran a new wire from the right housing to the left housing – this will be the brake light for the right side.

With the new euro housings in place, the indicators are the top bulbs, black/red for the right side and black/yellow for the left side, the grey/black connects both brake lights and finally the grey/red connects all the side lights at the back of the bus.

We now have flashing amber indicators and nice red brake lights that don’t flash.

Evenutally it will be possible to replace the 9 pin relay with a more mundane euro unit – covered in a future article.