What's the gauge of the wire running from the harness under the seat to the rear lights on a 2013 Street Bob?

Pretty sure it's either 20 or 22 but would like confirmation before ordering.

 

I was just under there messing around and I don't know the answer. But I wanted to say your avatar looks like a good old dog, like a good old friend.
I apologize for not helping you but just had to say what I thought.

 

Thanks, man. Nothing like a 200lb Mastiff to keep you company.

 

I didn't measure it, but it should be 18 guage or larger. 1157 bulbs use 2.7a when both filaments are operating (.59a for running light, 2.1a for turn/brake.) Tolerance allowables and unpredicted resistance from solder joints, corrosion and metal fatigue will reduce load capacities.

18 guage max-recommended amperage capacity is 2.7a. 20 guage wire should be limited to 1.5a.

Most LED arrangements use far less current and could run on smaller wire.

Wire load capacities

 

Like said I wouldn't run smaller than 18AWG.

 

I'd say 20, have done a few, more than enough for a 1156 or 1157 amperage. I hate thick wires, so hard to solder.

 

I'm sure they're smaller than 18 because I got 18 to patch it all in after my aborted attempt to install my docking hardware and signal relocation kit (long story, not necessary now).

Looking at it side by side, the stock wire is definitely smaller than the 18g, I got for my temporary patch.

My main concern is making sure the wires fit into the connectors, pins, etc. once I put everything back together.

 

I recently replaced my entire harness when I made my tail light setup. I didn't measure the original wire, I just used the rules of electronics engineering. 20 gauge wire is not made for amperage above 1.5a and the stock bulb almost doubles that at 2.7a.

One thing to look at is the thickness of the insulator. Not all wire is created equal when it comes to the insulated coating. Some use much thicker insulation than others.

Of course, the worst that could happen is the wire gets hot and breaks or shorts against the fender. The 40 cent fuse will prevent any real damage.

 

Damn, you guys are making this much more complicated than I wanted it to be

I'm running the Custom Dynamics LEDs 1157s on the rear.

And, I'm going back to the base requirement for the wires to fit into the AMP connectors that will have to go into the one-into-three harness on my FXDB.

 

Sorry, I like to use my engineering books. I'm still paying for them, I may as well put them to use!

Anyway, item 42 in the photo is the crimp-on pin/connector. It shows that it's made for a range of wires between 16 and 20. Any wire in that range will physically fit the pin. The amperage of the bulbs calls for 18 or thicker guage.