Brake warning light wiring

[LisaB4]

My bus came in boxes, so can anyone tell me how this wires up? (1980 westfalia, so old style fusebox).
Where do the 2 round connectors go? And the loose wires? I've got blue/ black, black, grey/green.

[LisaB4]

[Robsey]

The round connectors plug onto the brake light switches on the underside of the master cylinder.

Assuming you have 3-pin switches, not two pin.
There are two switches, one for each brake circuit (fluid circuit).

The third pin on each switch is for fluid warning.
If you only have one switch, then you can leave the other round socket disconnected.

As for the single wires, these will be for the electronics bit for the brake fluid warning bulb, and the output to the hand-brake switch.

I will update which is which momentarily.

As blue/black goes to both pressure switches, that will be your fluid warning.

Black on its own is usually ignition live.

The Grey / Green should be the output to the handbrake switch.

I can see a brown which is obviously a ground / chassis / earth wire.

From memory, intwo pin vans switches, red/black and red/yellow are the wires for the brake lights.

Red/yellow - fused supply

Red/black - output to brake lights.

[LisaB4]

The brake switches are missing on my master cylinder and the wiring is from another bus. The wiring was also missing on mine. These round plugs have 3 wires, so I guess I'll install 3 pole switches.

[Robsey]

I suspect you are fitting these for your own peace of mind.

I am doing the same thing.
I have a 1983 van with no handbrake nor brake fluid warning light(s).
But I am making up my own loom to suit.

You can fit just one or both three-pin switches if you like.
As long as at least one is fitted.
They work in parallel, so act as back up to each other.

You need three pin switches if you want fluid warning.
Two pin is brake lights only.

Or you can get the reservoir cap with level switch.
Although I only see the cap for sale with the reservoir.
Not indevidually.