Wow, all over the place on a very simple issue. Randys, take the actuator off the differential, plug it in, hit the switch, and tell us what happens. Make sure the key is on and the engine is running in park or neutral. Does the actuator move? If yes you need to troubleshoot forward into the differential. If no, you need to troubleshoot back. Just like Johnny Cash, one piece at a time. Provide facts, get answers.