I have an older 23B, without the new factory LED awning lights. But, power run to them is the same as they run the motor power it's easy to find, just have to remove a million staples.
The wires run through the over head cabinet, in the dead space that makes up the shelf. I carefully pried up the shelf and removed the staples. I could then reach the wires. In my case I added lights under that shelf, so I could read at the dinette. Currently the shelf surface just sits in there by gravity
You can remove the stereo to gain access to the wires at the switch. Drill a hole for a dimmer switch. I found one online a couple years ago for about $10, and you could splice it into the wiring next to the switch.
If I get so.etime, I could try to figure out what that dimmer was.