1969 bus brake warning light wiring

I need help again! We are trying to replace the master brake cylinder. We have two of the "two prong" brake warning light switches, but the Bentley shows there are supposed to be 3 of the "two prong" switches. Also, In my 69 bus the wiring harness that is installed appears to be for a 70 or later model, had the 3 prong recepticles which I have cut off. I think I might have the schematic figured out for what Im going to do but I was wondering if anyone had any input?

You shouldn't have cut the receptacles off, they would've worked anyway. The brake light system is pretty easy:
Each switch receives 12 Volts on 1 "prong" and keeps it there, so until you press the pedal, it allows the current to flow through the other "prong" to the light bulbs on the bus' tail. The bulbs are grounded in the bulb socket, so all they need is the 12V lead current to turn on.

The master cylinder has 2 sockets for 2 switches because it is a "tandem" or dual master cylinder that divides the system in two parts: front wheels and rear wheels (so now you have 2 brake systems in one master cylinder) and it is capable of stopping the vehicle in the event of having a fluid leak on either front or rear wheel. The switches need the fluid pressure to work, so this means that if you lose the fluid pressure on either system there will be a switch alternatively helping the other one in case of an emergency.

The stock switches had 3 "prongs" so the 3rd one would let the driver know that there is a problem on the brakes activating the warning light on the dashboard.

Now that I've made a little explanation, let me tell you how to connect this: On each socket you have 3 cables: 1 black, 1 red/black and 1 completely red. Connect the black and the red/black on each "prong" of the switch and you're done, it doesn't matter where you connect the cables, just put one on each side. Nevermind the red cable, just insulate it.

In the case that the cable colors are different, use a test lamp to determine which cable comes from the batt/ignition key (some old VW vehicles' stop lights work with the ignition key at "on") and then touch the other 2 cables to determine which one turns the stop lights at the tail. Connect as prescribed.

If you do want to keep the warning light on the dashboard, you need to hunt down the 3 "prong" switches and connect, on the 3rd "prong", the third cable that goes to this lamp on the dash.

If you want you bus to turn the stop lights on regardless of the key (if this is your case), connect the cable coming from the ignition key directly to the battery, using a 15 amp fuse.

I hope this helped you, buddy. That third cable made me have a couple of headaches a few years back.

hi just a noob question but what happens if the original poster have continued with the said plan? i am a bit confused when come to electrics. doesn't it have a [You must be registered and logged in to see this link.] / brake switch??

[You must be registered and logged in to see this image.] Very thorough reply 1992VWBug! [You must be registered and logged in to see this image.]

Kevinlvy, not really understanding your question. The brake light switch / brake switch is the same thing.

Dragnfly, its very possible your '69 was built later in the year and the '70 wiring was put into use right before the '70 models were started. VW's kinda weird like that.