Do you have the winegard booster?
It is a wall plate, sometimes has a coax output on the front, also a button that turns on a green light. This is what switches from antenna to cable. It is on cable with the light off, antenna with the light on. I saw someone mention using a splitter to combine cable & antenna, I don't know if that would work, never thought about it. I did replace my bomb, box of many buttons, a year or 2 ago, got it on Amazon. Magnadyne VCS-10 5 input 3 Output... https://www.amazon.com/dp/B00SWGSESO?ref=ppx_pop_mob_ap_share