Battery or Key On power at the back

[MME1122]

I got this trailer wiring harness from Etrailer:

https://www.etrailer.com/Custom-Fit-Vehicle-Wiring/Jeep/Liberty/2011/118554.html?VehicleID=20111173585

The kit includes a wire to run all the way to the front to the battery. Is there anywhere in the rear I can pull battery power from? Or key on power, I assume that would work fine too. I'd rather not run the wire all the way up to the front if I don't have to. I don't have the factory tow package so there's no harness plug anywhere.

 

[klc]

The rear 12 VDC socket is always on, but you don’t want to draw much more than about five amps.