I'm nearly done converting my '67 P220 amazon wagon over to a dual-triangular brake system taken from a donor 1971 1800E. Except for a little bracket welding to the 1800E axle so that it properly mates up with the 220 suspension, and the arrival of a new brake booster standoff to get the brake booster to clear the steering shaft... I'm done!

So, now comes a troublesome part - wiring. My original brake system light was given both an aftermarket pressure sensor and an aftermarket pedal-release brake light switch. These have worked well. The aftermarket brake light wiring is complex with two distinct sets of connected wires attached to two of the three prongs on the sensor switch screwed into the original brass 4-way brake junction up on the firewall. I've no idea if this was even close to the stock sensor or wiring. My 1800E brake junction is a brass "H" block mounted to the left fender wall with a narrow single-prong brake pressure sensor/failure sensor.

I don't think the big sensor/switch from my original setup will fit into the H-block due to the six brakelines that attach to it. I'm even not sure if these two plugs even serve the same function! I do know that my old brake light system did not work with the sensor switch wires unplugged and that the 1800E system was also functional before I disassembled it.

I'm not sure how I should be wiring up this conversion.

I did save my 71E's brake light warning light, which I'd like to install on my dashboard properly, but again.. unclear how to wire all this up.

Any help is appreciated, even a clarification on how the 122 and 1800 systems were respectively wired. I have some greenbook resources, but if someone could point me in the right direction, I would greatly appreciate it