I am posting this update because I would have killed for this information during the past few weeks.
If you recall, I received and installed both a front and rear fuel sending unit a few weeks ago and the fuel gauge was still not working. After hooking up to my diagnostic machine, it showed the rear unit not working properly so I contacted the company and they sent me a new one.
I received the replacement rear fuel sending unit and installed the other day. Hooked everything back up and still the same issue, no movement on the fuel gauge. After some forum searching, I read that the wires run up to a harness somewhere within the front, right-hand side wheel well. Here are some pictures to explain the problem all along:
Remove clips and screws from mud liner and remove liner (FYI, removing tire would have made the task easier but I had no idea where the harness was)
Look to the left hand side of wheel well, at the bottom, near the frame
There are two harnesses next to each other, the harness for the fuel tank is on the left (with red clip).
Looking further down the wires, you can see the wire protection ends and the wires are exposed to the vehicles frame
I lifted the wires off the frame and the green wire (Rear Fuel Sending Unit), was cut in half
I then spliced and re-connected the green wire and the fuel gauge FINALLY WORKS!!!!!
So after multiple fuel tank drops, fuel sending unit replacements, and a great deal of frustration, the problem has been solved!!!