What is the "back up" fuse for on my '07 fjr? It has full time power but can't figure out what it powers. I am still chasing a power draw and I am wondering if it could be the culprit.
Do you have a multimeter? If so, rig it to read Amps/milliAmps. Install the Ammeter between one battery terminal and the cable that should go there. An Ammeter is a dead short, so it works like an extension cable on the battery wire, passing power to the bike. With everything OFF, the Ammeter should show only a tiny drain, just a few milliAmps to run the clock and bike memory. If you see a significant drain (100s of milliAmps or more), there
is your power leak. Remove one fuse from the bike, and check the Ammeter. No change in the reading? Replace that fuse, and pull out the next fuse. Continue this process until you find the one fuse that allows the heavy drain to happen.
This process will eliminate most of the bike electricals from the "suspect list." Track down whatever items that last fuse runs, such as lights, horn, et c.
If you do not have a multimeter, you can use a small instrument light bulb instead, with one side of the bulb connected to the battery terminal, and the other side of the bulb connected to the battery wire. If the bulb glows at all, it will do the job. You may need to shade the bulb in a dark tube or box, to see a dim glow happening. Just follow the process above, looking for the fuse that puts out the light when that fuse is pulled.