These (GEM) modules are "truck" specific.
Meaning, they control qiute a few things, power windows, lock, etc, etc.
Keep this in mind, "your" module contains the "software' for "your" truck, if the one you purchased, doesn't completely work, as in, "now your windows don't work" you'll have to download the software from your old module to the new one. This is done through the OBD port,
Your old module will have to be re-installed to do this,"if the new one needs an update".
Also, I'm still in the process of checking my problems, cold weather, no garage to speak of etc, etc, has put this on the back burner for now, for me.
BUT, I did learn that, in testing your motor connections, (the two plugs to the transfer-case motor for the 4x4) you need a load on them, a tech suggested, to use a headlight, wired to the two prongs.
This will put the required "load" and if the light, lights up, (for a couple of seconds only and pulse's) the circuit is good and your motor is defective.
A meter, (Digital Volt meter) will NOT pick up these pulses, it doesn't have time to "catch" them.
Your situation does sound like it's the module behind the glove box.

fuelman, I have a question, does the module on your 250 behind the glove box have a center plug missing on it. No center plug but only on both ends?