Yes, I figured the switch was a temporary set-up for testing and experimentation.
However, "Temporary has an amazing habit of becoming permanent."
From what I could see in the picture you posted, it's likely there's two outputs from your power supply. One would be the 3 amp "charger" output, which is what you're apparently measuring with your multimeter.
The other, which you may not have noticed, would be a higher amperage output for supplying the coach system circuits directly, bypassing the battery when 120/240VAC is available.
