4WD won't engage

[brettdn]

I have replaced the actuator and transfer case switch and my 4WD still won't work. I hooked up my power probe to the actuator to engage it and have the lever in 4HI and works that way but when I have the trucks electrical system it do it by itself nothing works. Could there possibly be a wiring issue or something more serious? Obviously there is nothing mechanically wrong if I got it to work by using a power probe.