Originally Posted by TacomaJoe
The jack is something that I have debated because it would put an extra layer of antitheft (can't raise/lower tongue).
You would also have to make sure the aux power pin on the 7-pin connector was also disconnected from the jack power wire. In my two trailers, the aux power from the 7-pin connector, tongue jack, and emergency breakaway switch were all tied together and then straight to the + terminal of the battery, bypassing the battery disconnect switch.
To energize the tongue jack, just plug the 7-pin connector into a power source, even if the battery is completely removed.