Tusk Enduro Lighting Perplexity

So I decided to drop the coin on the Tusk Enduro lighting kit and I spent most of the day installing it. In the end, the blinkers and the horn work. I did not mess with the head light switches.

I cannot however get the taillight or the brake light to work and there is a unique complexity right at the connector.

In the picture attached, the three wires at the top of the photo are coming from the harness. There three wires at the bottom of the photo are coming from/going directly to the tail light / brake light.

When I power the system, I get no tail light or brake light but if I stick that pointy tester thing into the connector at the top, I find that only the red wire is hot.

At the bottom, the black wire is hot, nothing from the red, and when I stick the pointy thing in the connector at the yellow wire, I get no indication of power but the tail light lights up. Seems like I'm making a circuit?

so is it possible that the wiring coming from the tail light is crossed?

Just using the one that lights up. Probably doesn't help the situation.

So that yellow wire comes from the taillight and when it's grounded, the light taillight comes on. Can I then just ground the yellow to the frame and be done with it?

Turns out it was a defect in the harness. Rocky Mountain ATV sent me a new harness free of charge and BAM, it works GREAT!