4x4 DOES NOT ENGAGE.

When turning the **** to engage 4x4 to high or low, nothing happens,
not light on the dash indicating 4x4 no clicks , nothing.
I checked the fuses, the big one in the engine compartment, and the one under the dash, drivers side.
Is there any other fuse or electrical connection I might be missing ?
Just to mention, this started happening after my alternator died. I replaced it , since then , no 4x4...
I know the problem is electrical, but waht ? ....
Any input ?
Thank you
1997 F150 V8 4.6 auto 4x4


