Seeking help with electrical problem Options

[JoeSh]

Hi
My 73 2.0 914 has a few odd electrical probs I'm trying to fix. The most obvious is that it won't turn off when the lights are on and my foot is on the brake. Corrolary: lights on key on engine not running pressing brake primes fuel pump.

What I know/have done: by pulling fuses narrowed it down to fuse 8 circuit. Oddly (to me) measured 8v on circuit 7. I assume it should be 12.
Cleaned all the grounds I could find. Attached a long wire from batt negative to my multimeter and metered at all the grounds to see if there was a difference in potential. Less than .1v.

The wiring is somewhat burned and rather hacked under a PO. Would love to both fix this issue and get the wiring closer to factory. Haynes manual seems a poor reference to understand the factory connections, wiring design, etc. Can you suggest how to proceed? Is there, for example, a picture/annotated diagram of what wires are attached to the fuse panel? Such a rats nest!

[GregAmy]

http://web.archive.org/web/20161027114644/...al_diagrams.htm

[Retroracer]

I would recommend dealing with any hacked or obviously melted/burnt sections of wiring or loom before even starting to debug this. Best option is a replacement loom, but that is a high $$ option....

Over current faults in a wire that is part of a loom can lead to melted insulation and intermittent connections between that wire and others that happen to be in the same loom; also you can get high resistance points in the wiring too, leading to voltage drops on the loads. This sort of fault can present as all manner of weird voltages showing up, as disparate items try to current share, and also strange functional interactions - ask me how I know!

Get the loom as near stock as you can, replace any and all suspect sections - then proceed to debug. My 2c.

- Tony