WMark… seeing your photo I’d say that is your “dash switch” and that there should be another switch present at the map light. But my belief of this is solely based on my motorhome and a few other members that have posted here about their RVs.
My motorhome has two map lights driver and passenger. I rotate the dashboard lighting dial all the way until it clicks and then there is a small switch at the light as well. For the passenger there is the dash switch I mentioned and the same small switch at the map light.
I looked at the online version of your Operator’s Manual and found this information on the map light switch.
Since your Operator’s Manual only mentions the dashboard lighting rotary knob perhaps that is all you need on your 2009 Journey to activate the map lights and the armrest switch lets you turn the passenger light on and off.
Here’s a link to your online Operator’s Manual followed by the map light instructions:
https://www.winnebago.com/Files/File.../09Journey.pdf