:stupid That's exactly how I got mine to go down when I 1st got it.take off the access panel and run jumper wires to the motor connectors. hook it up one way and it'll make it go up and hook it up the other way will make it go down. i had the same problem when i got my bronco almost 5 years ago, thought the motor was bad, but it was just the wires.
I imagine on the newer trucks there is a safety mechanism to stop this. However, I know on mine there's nothing like that and when I had this problem, it was a fast and easy way to access the wires and with another person there took about five - ten minutes to get the top bolts off, lift it up, and lower the tailgate. Didn't have to worry about running wire leads to round-a-bout power the motor.I don't know if lifting the top off would work....I know in my truck it wouldn't because theres a safety thing in there that won't let you drop the tailgate unless the window is completely down....but it could work for an older year.