1973 911E Targa -- Horn Wiring

[Vintage56]

I am relatively new to working on 911's and by no means am I an expert in 911 wiring. Of course, I don’t want to melt the electrical system! So, am looking for some expert advice.

I just recently acquired a 1973 911E Targa. I have a few electrical issues that may or may not be related. Read on.

For some reason one of the two trumpet horns is missing (the one that should be facing forward) but all four electrical slip-on connectors appear to be present in the left front wheel well, but are disconnected. There is a severed green wire that is just laying near the one mounted horn. I assume the green wire is ground? I also have no power to the trunk light, even though the wiring is connected to the hood switch and to the nearby bulb holder. There is also no power to the interior light from the two door switches, even though both switches have wires attached and wires are up in the roof for the bulb holder. (This being a Targa model, there is only ONE interior light.) Interestingly, all four corners of the parking lights and the two headlights work, the dash lights/gauge lights work, and even the clock works. Also, all fuses are present and are intact.

Was looking to see the correct wiring set up for the two horns as there may be a harness I can use? Since the headlights, parking lights, and turn signals all work, don't want to replace the entire headlight harness. I am just not sure how to proceed. Seems like I have multiple issues, but not sure if they are related to the horn not being connected/grounded or to something else.

Thanks everyone for any detailed guidance, sketches, or diagrams....

[timmy2]

Black with yellow tracer is horn power, brown is ground.
No green wires in the factory headlight or horn wiring harnesses.

[timmy2]

Should look like these.