There are two kinds of Winegard switches uses on most motor homes and a 3rd one that is rare, I will cover the first two and how to find them
On many higher units there is a Box of Many Buttons ... it's the button on the left (usually) marked POWER. (That was easy wasn't it)
This box selects several sources, (ANT, Cable, Sat, DVD, VCR, Aux) and sends them to the televisions, it can send different sources to different tv's.
The other one is a wall plate.. USUALLY whit but no guarantee.. If you have this it should have a coax cable hooked to it that goes to the main TV, it will also have a 12 volt outlet, and a small light light on, Antenna on.
The rare one is a wall plate with just a switch and light.. Need not have the light, Need not say Winegard on it, any toggle switch will do. I've actually seen ONE of these in my travels.. Just one.