[JRTJH]

I believe you'll find that you have two "power sources" for the lights that way. You'll be sending 12VDC to the running lights from the upfitter switch AND 12VDC when the light switch is turned on. If both are on at the same time, you'll have a direct short and blow the fuse under the hood on your truck.

If you remember to turn off the upfitter switch before turning on the lights, I'm not sure what would happen. I have the upfitter switches in my truck, but I'm not familiar with the way Ford wired the upfitter switches through the ignition circuits in the "central computer" and whether there's an "always powered pin" somewhere that would cause problems for the upfitter switch wiring.

It used to be that you could look at a wire and tell where it starts and where it ends. With today's technology, that's no longer true. The "flux on the wire" controls the bias on a circuit in the computer and that determines what happens in the upfitter switches. Whether any of that would affect the bulb monitoring system in the computer through the headlight switch ???? They made them way too complicated for an easy mod.

If I were intending to power my camera from the upfitter switch, I'd wire a separate line with a separate plug at the 7 pin receptacle and run that line under the trailer to the camera. I wouldn't try to integrate it to the 7 pin/upfitter switch/headlight switch/sway control/stability control/brake control which are all tied together to monitor trailer performance....