Welcome. There are a few possible causes. The first is the switch on the transfer case just above the shift lever. This sends power to the front diff actuator to engage the diff.
Check the 4wd fuse in the left dash fuse block. If that is blown, then the front axle actuator is likely damaged. Once they short out, they pop that fuse. This actuator is threaded in the front right of the diff housing.
How about the 4wd fuse in position 24?
OK, do you have a test light?
OK, its late here as well. Sleep well.
Ok, that does not make sense. Center, terminal B is grey black.
Look at the lower left of the schematic.
It may be that a repair was done, and honestly if the schematics were always correct, my job would be easier.
Try jumping the power wire to the blue and see.
yes Brown to Blue.
My pleasure. To get me directly the next time, in the title line put "For BlueGorilla Only" and I will get it as soon as I am able.