98 1100
Noob 1100 owner here
"Key" switch on left in pic
P.o. didn't know what this is for either so I came to the Gods for help.
Thanks in advance, Marshall
Phil is right, er....correct. The bottom item is a powerlet. It took me a second read to realize that you were not asking about the switch above (to the right of) said powerlet. My guess is that the switch controls the powerlet - switch off, no power, switch on, powerlet works. This is only a guess.
Powerlets are like cigarette lighter sockets (cls), but the European or BMW version thereof. They are made to tighter tolerances (or so they claim) than our cls. The downside (if indeed it is one) to powerlets is that all of the pieces are expensive. For example, to get a powerlet to usb adapter you will pay anywhere from c. $35 to $49 for the genuine article. There do not seem to be too many aftermarket powerlet plugs. The upside is the quality is outstanding. You get what you pay for.
I found that for my heated clothing, I needed a powerlet to coax connector, bought one that was too short (duh - measure first you dummy) and had to buy a longer one. I could have used a coax extension but that would have added one more connection that could pull loose and take me far too long to find when it did.