I'm all straightened out now. For some reason I thought both the 7 pin plug and the 4 pin plug were tied together. Then I didn't realize the 7 pin plug there is needed to "complete the circuit" or "turn on" the 7 pin leads.

 

If your truck came with the factory tow package you may not have a pigtail in the bag with the instructions and the relay. The pigtail may be plugged in already under dash with the brake light and trailer brake power leads crimped together and the rest of the leads tied up out of the way. This is how mine was from the factory.

 

Got my relay and pigtail today. Plugged the relay in, plugged the Hoppy into the 7 pin receiver plug, plugged my 12v light bar in, turned the key on and tada! it all works. For me the Hoppy and light bar was a better fit to light up the bed when needed over wiring in some under the rail lights or a live 12v plug under/in the bed. Well at least for now.

Again big thanks to whitecrystal1 for the extra relay/pigtail!

 

Is the 12V out on the 7-pin connecter live all the time, or only when the accessory or ignition is on? I 'get' that you have to plug in the square relay that comes with the tow package. Thinking of wiring a backup camera and it'd be nice to tap the 12VDC (in-line fuse, of course) from the *** end of the truck rather than going all the way forward to the fuse panel.

 

Glad you got it.
I might get me on of these. look pretty simple and There when you need it.

 

Mine only seems to be live when the key is at least to the "on" position.

 

I towed a car trailer with my old Lariat to Arizona. It came with the factory Tow and Go package. I did have the relay with my truck, but I never had to use it to "make the 7-pin connector work." Mine just worked from the factory. I didnt install anything, so I dont know.

 

That is correct. It is designed that way so that a bad coach battery on a travel trailer will not drain your tow vehicle battery and leave you stranded. It will charge the coach battery when the ignition is on and when the tow vehicle is running.