You don't say what model Montana you have, but assuming your have a front bedroom, you do have to change a jumper. Either in the closet or near the TV is the external antenna on/off device. It also has the satellite input for the bedroom TV. There is a jumper from the satellite input to the TV. This jumper needs to be moved from supplying the TV to the connection which feeds the basement outlet.
Carl (n Susan)
There is more to life than fuel mileage.
2012 Montana 3700RL Big Sky Package towed by a 2015 Ford F350 6.7L PSD 4WD CC LWB