Turning on the running lights through the trailer plug

Yes, I know this has been a topic that has received a lot of flames, and I'm not asking to be able to use this while camping. I was just playing around with the fiver tonight in my driveway (just finished packing bearings today), and was wondering if I could make the running lights come on using a jumper across the plug. Just a curiosity.

I tried jumping across the hot lead on the fiver plug to the one that turns on the running lights and it doesn't make them come on. I put the end of my test light into the hot lead of the plug and grounded it against one of the bolts on the hitch and the red light of the test pen comes on. If I reverse it and put the alligator clip of the test light into the hot lead of the plug, and then put the pointed end of the test light against one of the bolts on the hitch, the test pen has a green light turn on.

Anyone play with this and have an idea of how this is working? Like I said, not something I intend to use. More just trying to understand my electrical system.

Wondering too, if I can make the brakes turn on and off while sitting in the drive this way.