GM SUV's and Pick up's only take 10 seconds holding two buttons to tow 4 down.
(I'm ready to install the relay board you made for me but I'm gonna need your help)
The Expeditions are NOT towable all 4 down. You can check with Remco and they may have came up with something.
Could get a 2 wheel drive and use the Remco! FWIW BK
Or ya could save that $ and come on down to the Rally this weekend and we'll all help ya think on it over a cold 1! ! LOL!