My Excursion is stuck in 2wd. It worked one morning, then it didn't that same afternoon.

I've checked all fuses that resemble a related fuse in the fuse box.

I've replaced the dash switch, Transfer case shift motor and ESOF/GEM module behind the glove box. I've swapped around the relays under the hood on the drivers side fender well.

I ran a hot & ground to the 2-wire plug on the x-fer case shift motor to have it move the ex back into 2wd (replacing the shift motor required me to manually put it in 4hi with a wrench).

At this point, I'm thinking it's a wiring issue? Has anyone else been in this position? Any guidance on where to go next?

 

What's not working? Dash light? Hubs?

If it's the hubs not engaging....They're vacuum actuated, I'd start checking lines bud.

 

Transfer case isn't engaging.

 

In that case I'd start reading wires in the harness to ensure there are no shorts and no breaks in the wire. Seeing as how you've replaced a lot of stuff already that would otherwise normally be suspect, I'm leaning towards a wiring gremlin somewhere.