Just to follow up, since I had to replace my masthead, I decided to go ahead and run all new wiring while the masthead was off.
All wires pulled through the internal conduit easily. I had also found a new square four pin trailer plug that was like the one originally used so I wouldn't have to rewire the deck side plug.
Glad I'm not color blind.
The duplex running to the mast top had black and white wires. The new duplex wire was yellow and red. All right, the mast top light had red and black wires so red to red and black to yellow.
The triplex had black, green and white wires. The steaming/deck light had white, yellow and brown wires. White was common, green was steaming and brown was deck. I guess that made sense to someone but not to me. So White to black, brown to white and green to green. (now that makes sense).
Then went to the bottom of the mast. The new trailer plug had the same four colors as the old one but thought I had better check. Sure enough, the brown and yellow wire had swapped positions.
So plug white common to duplex yellow and triplex black commons. Old plug yellow is now brown and goes to triplex white. Old plug brown is now yellow and goes to duplex red. Now the last wire. Oh wait, this can't be right.
Old plug green is new plug green and goes to triplex green to green wire on light. Boy somebody really screwed that one up.
In the end I had notes on scrap wire, scrap cardboard and photos. Came home and documented the color codes just in case but sure hope I don't need to do this again.
Here's a diagram I made up to document the connections.
View attachment 150701
