

2016 Jeep Wrangler tail light wiring question
I bought my Jeep a few years ago from friend. They had a tow hitch installed but no trailer light harness/adapter (they just used it for a bike rack). Yesterday I'm driving and message comes up that the bulb is bad on driver rear. I have a few spares and tried those-- no luck. Running lights work, but no turn signal. Tried on the other side and they work. Even tested them with a 12v source. Bought new ones thinking maybe they're wonky and neither of those work.
I thought maybe the trailer harness has gone bad or something. Hooked up an analog volt meter to the 4 pin trailer connector so I can see the needle swing if the turn signals work on that. Yep, see it swing to 12v then off with the blinker.
So I'm thinking maybe the pigtail/harness is bad going to that light. The first picture/connector looks like the factory harness b/c it goes up into the body (not underneath). The 2nd picture shows black taps going to the light sockets and then underneath the body. I took off the passenger side and same thing on that side. I follow the wiring down and they connect along with a ground connection with an after market spade crimped on. Then it goes up over some cross member and I can't tell were it goes (yet-- it's 110F outside and I gave up for now). I asked the previous owner and he wasn't aware of any wing mods in the back (I have a blue ox towing setup as well in the front).
I was looking to just replace the pig tail/harness from the factory connector to the light socket- everything I see shows a factory style connector right to the sockets. No wiring/taps needed.
So the question is-- are the tail light just connected to the factory harness via something that goes in picture 1?
Edit. I think I figured out what that wiring is. The jeep has a flat tow setup with blue ox etc. there’s a connector up front under the bumper. The tow vehicle powers the tail lights when you’re flat towing it. When the previous owner had that system installed they added the harness and spliced onto the wires going to the sockets. Yuck. Now I have to figure out which wire(s) have a bad connection.