96 k1500 5.7, 4x4 shifter on the floor. 4x4 wont engage. installed a new actuator and still nothing. I have 12 volts on the plug with it engaged but the acturator will not move with it out of the housing. I put 12 volts across the acturator from the battery and it moves. I had a 3 wire connector on the original actuator. The new one came with only 2 wires. The 3rd wire goes to the bundle of wires on the transmission plug. what am I not getting here. What does the wire to the transmission do?

 

i think goes to your trans case so you cannot shift from 2hi to4lo without being in neutral

 

i dont know anything about this but im going to take a lucky guess.

it can either be a ground or it can be some type of sensor that will kick it into 4 wheel when the gears are lined up right so no damage is done to the tranny

 

That sounds more like it

 

hope you get your problem fixed
keep us posted