It does have a limit switch. However, if your trailer has ever lost power when the tv mech was in motion, it will auto reset. With tv up, look under the left side of tv and you should see the control box. If it is blinking green very fast, it has to be re-tuned. You can do this with the little button next to the flashing light.
You can always call Heartland service for more advanced instruction. 574-266-8726