A couple of things come to mind:
1. Make sure the power is OFF on the Winegard RF switcher;
2. Make sure the RF switcher is switched to the input that is for Cable TV. It will not be the TV input. It will likely be AUX;
3. At the TV, make sure when you are doing the Auto-Tuning, that for signal type, you are telling it Cable TV. This sets the tuner's frequency plan in the correct mode.
Failing all of that, I would suspect the wiring. Could be a connector issue or a cable issue. To test this, I suggest you slide the TV out, take your portable cable TV wire that you use outside, connect it to the Cable TV connection in the campground, run the other end through the window nearest the TV set and connect it to the antenna input connector. Then go through the auto-tuning for Cable TV and see what you get. If it works, you have a wiring/connector/switcher issue. If it does not work, the Cable TV jack on the campground may not work or your jumper may be bad.
Good luck and let us know.
Jim