My truck is a 2000 4.0L XLT automatic, production date January 2000, manual locks/windows, it has live axles, but when I looked in the passenger kick panel where I was told a 4x4 control module would be, there wasn't one, just two studs where one would be mounted and no connector that I could see. The engine and transmission are both from a 97, I'm not entirely sure if the ECU was swapped from the 97 or not, if that matters, I was able to get in contact with the owner that did the engine swap so i could find out if that makes a difference.

The issue I am having currently is SOMETIMES the 4wd will engage normally but only in to 4Hi and usually only once and even then, for all I know, the 4wd isn't actually engaged at all, but the light does come on and stay on.. If I attempt to put it in 4HI again, I just hear clicking in the dash for a few seconds then it stops and no 4Hi light comes on. If I put it in neutral and try to engage 4Lo, same thing, clicking then no lights and it does not engage. I am doing a LOT of work on the truck right now so almost every day I disconnect the battery for most of the day (sometimes days at a time) from what I have noticed, the 4wd will only engage once when I reconnect the battery then not again until it is disconnected for a while.

I was going to replace the transfer case motor anyway, but as far as the other electrical stuff... I don't even know what I have if I need to start trouble shooting/replacing other stuff.

 

Your 2000 Ranger may have come with PVH 4x4 so the GEM module behind the radio is the 4x4 controller
And from the "clicking" in the dash that would tend to confirm that, in 2001-2003 the "clicking" would come from passenger side kick panel

Previous owner may have locked front hubs full time or swapped hubs and axles to make it Live axle, but GEM controller would work either way

The GEM module uses a dual relay box(shift control) located behind it to activate the shift motor, thats were the "clicks" come from

Both relays in the box are grounds when "open", so GEM just activates(closes) 1 relay to send 12volts on that 1 wire so shift motor turns Clockwise, or it activates the other relay to send 12v on the other wire so motor turns counter clockwise
So works the same as power windows do, reversing polarity to reverse direction, up or down

If relays are clicking then 4WD switch and GEM are working, so I would test shift motor, remove it and test using 12v and ground directly to see if its working/turning
The 4WD lights come on when the contacts(sensors) in the shift motor shows that transfer case shift rod is in the correct position for selected "gear"

Shift motor disassembly seen here: https://www.explorerforum.com/forums...-motor.123542/
The motor brushes getting dirty and worn down causes them to be intermittent
It also shows you the contact(sensor) wheel in the shift motor housing, its tells GEM what position transfer case is in

Wiring diagram below, check fuse #3 in ENGINE fuse box, 20amp, its the 12volt power for the shift motor, just for the shift motor

 

Thanks for the info, I would have never guessed in a million years that both the GEM and 4x4cm would work for both axels... and I still don't understand why... I went ahead and ordered a transfer motor, with Autozones 20% off $100 and free next day shipping going on now it's almost silly not to, I should have it in tomorrow or Saturday so we'll see what happens!

 

The GEM had the 4x4 control and separate dual relay box, and it also had the PVH solenoid control to lock front hubs

The 4x4CM had the 2 relays inside it and didn't need PVH solenoid control

Basically either can control the shift motor which never changed from 1983-2011 on Rangers, and most Ford 4x4s use the same shift motor
There are 7 wire and 8 wire shift motors(all connectors are 8 pin), but that has to do with the Brown electric clutch wire being in the connector(8-wire) or on its own(7-wire)

 

I finally got the time and weather to swap the transfer case motor and it worked, 4wd (4hi and 4lo) engages with no hesitation and pulls like it should. When I unbolted the old motor it literally split in half in my hands, it looks like the time I did get 4wd to engage it actually split the case of the motor. and after that it was just spinning free. Thanks for the help narrowing down the issue and explaining some of the 4wd nonsense to me!

 

Good work

Thanks for the update and the FIX