OP here - update. I wrestled the power panel out of the cabinet and discovered that the blue/white wires are not connected to the power panel, but connect to a black/white pair that enters the wall bundled with all the other wires coming from the power panel. That means that the wall switch for the slide gets it's power from some other location.
If it doesn't come from the battery and it doesn't come from the power panel then where?
This also brings up the question, is there also a fuse for the power awning switch which is located right next to the slide switch?