i have a 91 z71 that wont lock in 4 wheel ?

the transfer case locks in. but front wheels still do not lock. i have replaced the actuator and still nothing. it is something in the transfer case itself i traced down the wires and the transfer case has power to it but, it does not have power coming out( going to the actuator). what could this be?

your automatic locking hubs may need to be replaced.

You either have an electrical switch problem in the transfer case as that is where the power comes from to the actuating switch assembly in the front diff or you have a mechanical problem inside the TC which is not moving the switch inside. More diagnosis, try simply jumping the switch connector at the transfer case to see if the electrical works to the front diff. If it does, remove the switch and manually operate it while checking the continuity through it. If you have both states, the switch is good and it's inside the TC.