Sorry you wasted so much money shotgunning the problem. It is always less expensive to troubleshoot the problem before spending your hard earned money

. One of the single most common problems witha rear window is the safety switch in the driver side latch. A lot of people end up bypassing it, as I have for several good reasons.
What you need to do is to get a voltage meter and probe the wires going to it while some one operates one or both of the switches. The Black with white stripe wire should be hot at all times it isa the power source for the tailgate key switch. If you are operating the switch on the tail gate, then the other two wires on that switch are used as ground return back thru the dash switch. If you operate the dash switch, then one wire feeds 12V to the motor while the other acts as a ground return and vice versa for the other direction.
Also it would be helpful if you include the truck year and some of it's other vital statistics in your signature. That will aid in a better guess on our part

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Diagram attached.
Good luck,

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