my 98 jimmy (np1 , 3 button) would always go into 4wd fine but sometimes it was stubborn about going back into 2wd . there were no codes and everything else looked / tested fine so i always assumed it was the TCEM because you could hear the motor try put the case back into 2hi .
today i go and buy a reman TCEM and install it . when i pushed the 4hi button i could hear the relay in the dash click but got nothing from the TCEM not even a sound , uninstalled and reinstalled 3x , same thing.
i thought maybe i got a bunk reman so i exchanged it for another , install it . SAME THING .
Now i returned the reman motor and got my original 1 back and still nothing will work ..
so now i have nothing , before i at least had a 90% working 4x4 now 2 motors , few hrs of work and i have a 0% working 4x4 .

i have gone over the plug and wires near the motor and it all looks good.
before doing this i got no codes , now i get code 3 & 4 . what did i screw up ? i did nothing but unplug the motor , remove the 3 bolts and install 2 new motors and now the original ..

 

that's actually not that hard-running yourself over with your own truck, i mean.

as for your non-functioning 4WD, have you checked the switch yet? how about the wiring? since this became 0% working after you touched the TCCM, start inspecting the plug harness there for any loose or damaged wires.

also do the same @ the encoder motor. you may have had some damage down there from something getting kicked up.

 

as soon as the weather cooperates (figures it had to rain today) i am going to check the wire harness , that is really the only thing that has been touched .

if that does not work i was considering removing the windshield so i can do a running dive off of the hood while driving ..

 

honestly dude, chill out. It no use being so dramatic it wont fix your problem any faster. Go to a junk yard and grab a switch most of the time you can just pocket it. If there is nothing wrong with the wires try the TCCM fuse maybe it popped while installing something.

 

updated the original post ...