Headlight - Taillight Wiring

[mgm60]

So I’m mapping out a hodgepodge of wiring on my 36 Roadster with a plan to rewire. The car had one of those cheap 7 wire turn signal switches which did not work so I removed it. When I rewire I plan to use a Yankee 960 four wire switch.
When I pulled the headlights to check the wiring I found this Frankenstein retro fit. Looks like the builder modified for LED bulbs and also added a second bulb for the turn signal. Also isn’t the rear light suppose to be a two wire connection? Looks like a third wire was added to support turn signal.
Any thoughts on what I’m looking at here?
Mark

 

[JayChicago]

Doesn't look so bad to me. I would try to clean-up and use what has already been done.

I believe the third wire at the taillight, the black wire, is a ground. That's not a bad idea, as poor grounds are often a problem.

 

[TJ]

If you go to the 4 wire switch you will have to add extra lights at the back. The 7 wire switch incorporates the brake lights with the stop lights so you can use the existing tailights on the car. No extra lights needed at the back. Check out the Signal Stat 900 seven wire switch.

 

[mgm60]

TJ I searched this site and others before I bought the Yankee 960 and found several suggestions on using a Trailer Converter Switch for use with a 3 or 4 wire Turn Signal Switch so you can use the brake/tail lights for turn signals as well. Thought I was going to have to add some front turn signal lights but looks like the PO added a bulb for that in the headlights.

 

[TJ]

I don't know anything about a Trailer Converter Switch, but it seems you are adding another piece of hardware in the wires when you don't have to with a good seven wire switch. I also have no idea what that converter switch would cost, but my guess is when you add the cost to the four wire switch it will be more than the cost of a good seven wire switch.
So I checked e-Bay and that switch you want to add is about $20-$25 for a good one. The Signal Stat 900 is about $35 for the seven wire.