Originally Posted by White Gardens
When doing mine, I use a jumper with two alligator clips.
I have one constant power wire running to the rear of my truck to power my break-away battery. I find the constant on my truck side and clip the power wire to it. Then I clip it to a bullet connector in-line with my blue break wire. Basically I disconnect it and clip the alligator clip to it.
I've got the trailer jacked up and on stands and I check each wheel to see if the magnet has engaged and the tire isn't moving.
Just pull the safety cable on the break away box and it will lock all four wheels down. Do this after getting all wheels off the ground and unplug from your truck.