Greg,
I also have a 2010 2551 and it does have the amplifier with the button and red led light, it is in the cabinet over the passenger seat.
As the others have said, you have to have the light on for over the air reception and off when cable is plugged into the rv. When on a road trip staying in different places each night it can get confusing; one night on antenna and the next may be on park cable. Now my wife reminds me to check the amplifier if I am having trouble with the TV reception. And as Barry said, you also have to switch the TV between cable and "air" antenna input.
I purchased the wingman to help reception in remote areas like Quartzsite, AZ, it works.
Bob