I have an 04 silverado 1500 LS with electric 4x4. But before I get flamed.. I've done as much research on the matter as I can before I got to this point. I tried pulling the fuse and cleaning the grounds up. The transfer case motor, axle actuator and dash switch have all bee replaced. Tried swapping in 3 different TCCM from the junk yard with no affect. The switch lights up with all lights when I turn the key as usual then goes right to 2wd as it should but when I click 4wd auto it flashes and nothing. The neutral light does not come on when vehicle is in neutral. I can hear the transfer case motor clicking and or trying to engage but nothing. Looking to get some opinions on what I need to do all fuses are good.

 

So these trucks have a lot of ground issues. Did u check the ground under the cab on the drivers side? That's the last thing i can think of that you haven't already tried.