1996 Silverado Z71 4x4 Problems

We are having problems with the electronic 4x4. When in 2wd the front driveshaft from the transfer case does not turn. But when the 4hi button is pressed, the drive shaft now turns when the truck is moving, same in 4low. However, we jacked up the front of the truck and gave it a bit of gas, and the front tires do not turn. The lights for the 2hi, 4hi, 4lo do not stay lit, they just continuously blink, they don't stop, they just keep blinking. Anyone know what could be wrong?

We have tried disconnecting the positive terminal for 3+ minutes and trying again, still nothing. Like I said above when locked into 4x4 the front drive shaft spins with the truck moving. We recently had the seal replaced between the passenger CV axle and the front axle tube. Before it was working, now it's not. Before when the front was jacked up you could crank the truck, lock it into 4x4 and then in neutral you could spin the driver side front and it would spin the passenger side front the opposite way, now when you spin the driver side front, the passenger side won't spin at all. I think that rules out the transfer case. What else could it be? I noticed two seperate plugs that are on the front differential. One goes into the side of it and has two wires, and the other goes above the axle tube into the top of the differential. What are those two seperate plugs for?

What transfer do you have?
Does the front axle lock in?
Fuse good?

Driver side door panel fuse at dash, Tcase fuse at location 2 is fine, same with 4x4 fuse at location 24. Both are good. I don't know what transfer case it is. It's actually a friend of mines, I'm trying to help him out so we can get to the beach tonight. How do I determine transfer case? Front is obviously not locked in according to what I poster above. Transfer case turns driveshaft, but doesn't turn wheels.

From your post it's most likley the front axle actuator not engaging. It gets its signal from a switch on the tx case when 4hi or 4lo is selected. Lots of posts about 2 wire vs 3 wire actuators (thermal vs electrical). Hope this helps.........Steve

The actuator is on the passenger side. You could just remove the actuator and see if it works when you try 4x4. If it doesn't work test the wires for 12v, I think the wire that should have 12v when in 4hi or 4lo is light blue(if you have the electric actuator the brown should have 12v whenever the ignition is on.

If you have 12v on the light blue wire for the actuator and the actuator doesn't work replace the actuator. If you don't have voltage at the light blue wire, the transfer case switch probably needs replaced(its usually on top of the transfer case, drivers side, above the front driveshaft)