4x4 Push Button Problem (Not like others)

I have a 96 Sierra Z71 Extended Cab and have the push button 4 wheel drive. When I am in 2HI the "4 HI" button is solid. When I try switching to either 4HI or 4LO I will hear a "clunking" sound like it is engaging and then the corresponding button with remain blinking indefinitely and never turn solid. Now although it seems like it is changing into 4 wheel drive, it is not. It will get really torqey like it does in 4LO but only the back wheels move. I have tried replacing the actuator (it was a second hand one) and that did not work. Now I am really lost as to where to go next. I tried searching the forums here but no really solid answers on what I may try next. Please help me here I am getting stuck in the snow everyday and it sucks really bad. Thank you very much.

Daniel

Try reseting the trucks computer by either disconnecting the positive on the battery or unplugging the computer its self for more than 15sec. Also check to see that all of your transfer case wires are all connected properly and are not damaged in any way.

try replacing the transfer case 4wd switch it's self.