New Project - '71 Plymouth Valiant
Looks like the oil pressure sending unit wire to me. Should be down around the oil filter housing.
Well, you were absolutely right. I searched in the car and couldn't find a connection (bit of a tight squeeze), so I traced the wire back to the bulkhead connections and compared it to the original service manuals... "Oil Pressure Sending Unit". Now if only I could find the damn thing (I'll get it eventually, just been cold recently and I don't look for too long).
On a good note though, I found the original service manuals through mymopar.com and am finally able to make sense of the wire clusters under the hood. Given that most of them are extremely old and corroded with faded colors - all of which are wrapped in electrical tape - and will likely need to be replaced, I believe that I will just buy replacement spools and rewire the whole front end of the car. If nothing else, this will help familiarize me with it's layout and provide clean flowing current to the components.
Also, I believe I've found the issue why it's not starting now... Starter Solenoid. She will click for a second or so, then act like the battery is dead. Battery still reads 13v through the multimeter. She started and ran just fine for a while, so I highly doubt it's the starter itself. It seems more likely to me that there could be a short in the coil or possibly the hold-in section. OReilly's has a whole starter - including solenoid - for $50, comes with a lifetime warranty.
Will keep you guys posted as progress continues. More posts and questions to come.
PS: Does anyone know where I can get the Bulkhead Connections (Male/Female wire ends) for cheap?