Truck Stuck In 4wd

[whitextreme]

I know there are other topics open on this but I could not find the answer I was looking for. 1999 Silverado 1500 with the Autotrac transfer case. The truck is stuck in 4hi if you push the 2hi button it flashes, tries twice then goes back to 4hi. And on the switch it will go into Auto but the scanner says it is in 4hi and the front is locked when you turn. The front axle actuator runs and the transfer case motor runs. I also know the switch is good. If I pull the ATC fuse the front axle unlocks so I believe that is working but correct me if I am wrong. I have access to a Snap On Modis I can access the transfer case but I cannot switch it with that either. No service 4wd light on and cannot command it on but I know the bulb is good because it flashes on for a second when I plug the fuse back in. I cleaned the main ground under the cab, no change. The transfer case is full, but I need to check the front axle is it psible that it being low could cause this? I checked all the connections on the transfer case all are clean and tight. I need to know if I take the encoder off can I try and operate it with the switch will it damage it? Also where is the ATC Module I looked all over under the dash and could not find it so I can check the connections there. Anything else obvious I can being checking? Thanks.

[govtech]

have it scanned by a real scanner,always shift while slightly moving in neutral(no driveleine stress) ,the encoder motor sensor is a common failure,

 

the front diff actuator is powered up by the switch on top of the t case not the encoder motor,,

 

good luck