I've had LED headlights for a while and tbh, other than some light spread they've been great. However the other day they didn't fire up.
I pulled the panels off to take a look and found nothing wrong, checked the wiring and all seemed good, with decent earths (i've recently fitted extra earths). Even tried swapping out the dip/main relay with a known good one. When I put the meter on the 3-way bulb socket, it all seemed good, see attached pics. over 13V at dip and main. But when I put in a bulb, both LED and Standard Halogens were tested, they didn't work and I had no power at the bulb. For the time being I have fitted a temporary relay to trigger the dip lights, using the feed off the 3-way bulb socket as a trigger. But what is going on? Am I being really dumb? I'm the first to admit that electrics are my weakness. I welcome your comments.
Did you start the bike? Electric power needs two things, voltage and current. Voltage is like potential energy, and Current is how much "push" is available. You can have voltage, like water standing in a sponge ("I measure wetness here") and you can have current, like water running from a hose ("This wetness has some Power behind it.") You can charge up a toy balloon by rubbing it with felt. You have plenty of electricity then, but no real power. That "static" charge can flash as light through a fluorescent tube, but it will not light up a common lamp. Never let a LED get hit by a static charge.
All that to say this, a dirty connection can put voltage where you expect to see it, but with no real power ("push") there. Dirty battery terminals are a likely cause.of that symptom. The FJR has a problem with the ground connections getting dirty or corroded. Your bike may be in need of a factory recall, which will cost you nothing except riding time. A Yamaha dealer can check your recall status, by your bike's VIN number.
Even if the bike runs normally, the light circuits may be a victim of dirt or corrosion, and most likely it will be found at a connector. Unplugging and re-connecting each connector in the light circuits will probably show you which connector is now dirty. You can clean the dirty pins with contact cleaner and a stiff brush, or replace them if the connector housing is still good, or replace the connector outright. We have sources, if you need entire connectors. There is also a silver-bearing electrical connector grease which conducts, as well as keeping the contacts clean. You will need very little, on each contact. Electrical specialty shops should have this silvery grease. Avoid dielectric grease, which is solidly non-conductive; it prevents shorts, but that is all it does. A clean connector housing in good condition does that job better. Do NOT assume that a wire bolted to the frame is grounded. If the battery has a poor ground connection to the frame, then the "extra" ground connection at the lights will do nothing to help. All of these ground connections must be clean, shiny, and bolted securely at each end of each ground wire.
Since the voltmeter shows a voltage, the problem should be simple and easy to fix, once you find the cause. Keep us posted.