The hubs don’t lock on that truck. You need to get the front tires off the ground and remove the front driveshaft and actuator from the front diff. Then take a large punch (preferably a brass drift and make sure that the selector fork in the diff moves over. I should move about 3/8". Once you have moved the fork over spin the front yoke by hand and the axle shafts should both turn. In your case I would pull the tires since they are oversized and probably fairly heavy. Hope that helps.
Also the actuators really suck in those trucks and they are proned to failure. You can remove it from the diff then plug it back in and have somebody hit the switch to verify that it does infact work.