Found this info recently posted by "Pilottech":
"If you pull the plug on the actuator and use 12volt source to see if you have a bad actuator.
With the plug to the actuator in your hand and the lock of the plug in the up position the pins are #'d backwards 321 on the top row and 654 on the bottom. With + on pin 3 and - on pin 2 the DC motor will drive the actuator into 4WD and then +2 and -3 it will go back to 2HI. This will tell you if the actuator motor works or not. If the motor works then you can look other places. "
Ill give this a whirl in the morning!
Man I love this site!
