Mopar340
Wiring is one of the most frustrating procedures in an old vehicle. Wiring was terrible right from the factory and was designed to save copper (read $$$$$ savings for the manufacturers here) and now all our problems are multiplied by corrosion in the connectors, hot joints and the backyard mechanics modifying wiring from yesteryear. This is what I am doing to get my 73 back to working electrically.
First thing - GET A WIRING DIAGRAM FOR THE CAR. Then make the harness back to original if it has been modified. Heat shrink sleeves and solder to make the connections. Not those crappy crimp pieces of junk.
With the harness removed I labelled with masking tape, every dash connection. One of the gurus down your way can help you here as yours is obviously in the car. CP helped me and he knows every color off by heart.
Next I installed all of the park, tail, head lights, relays, other external stuff, etc and before plugging them into the harness check with a 12v power supply to see that they work. By doing this you prove if the light does not work that it is something else wrong. Use lithium (white) grease on all plug connections and bolted joints. (We use compounds to do 25,000 and 72,000 volt connections at work to avoid bad connections so 12V is more important in this case).
Biggest issues are what others have said here - column connectors and firewall connector. Check for a voltage signal on one side first then if you have something check the other side. No voltage on one side = one problem. Fix it, yellow the diagram and move on to the next.
Work on each circuit by going through the wiring diagram. And as each step is verified yellow that off on the diagram with a felt tip highlight pen to indicate success.
By doing things like I have stated above you will prove your good wiring and narrow down where the problems are. This is time consuming so don't get frustrated.I am also bypassing the firewall connector for the big red and black wires that go through to the ammeter. This will be done by bringing the wires through the connector and lug/bolt connection and shrink sleeve.
Hope I have helped here. Good Luck.
