Look on your air conditioner shroud inside the coach. You should find a little red LED. When the sun is shining on the solar panel, the little red light should be on.
BTW, nice coach, we had a pace arrow (2002) at one time, loved the 8.1L engine.
The problem with those solar panels, I also have one on my expedition, is over time they become less and less efficient, mine is completely gone. It won't charge any longer.
They are only about 5watts so really don't do a lot, not even sure that they would keep up with the minor drain from items like radio memory etc.
MGySgt USMC(R) 1961-1991
2001 Fleetwood Expedition
2013 Jeep Wrangler Sierra Toad