[DannoXYZ]

Hi Paul, welcome!!!

This is simple troubleshooting process:

I. Test headlight bulb. Measure resistance across bulb-terminals. Should not be open-circuit/infinite resistance. Also test by connecting power directly from battery terminals to bulb terminals using jumper-cables or test-leads w/alligator clips.


II. Test headlight fuse #5. Don't just look at it, electronically measure for continuity/resistance between two legs. Should be zero-ohms/full continuity.


III. Test headlight-socket ground. Measure continuity/resistance between ground-terminal of light-socket plug and chassis-ground. Should be zero-ohms or full continuity.


IV. Test for power at various points along headlight-circuit:

1. measure for +12v @ battery positive terminal
2. measure for +12v going into headlight relay
3. measure for +12v going out of headlight relay when bike's running if yes, skip to #7

4. measure for +12v going to headlight relay activation line when bike's running
5. measure for +12v going out of start/stop-switch to headlight relay when bike's running
6. measure for +12v going into start/stop-switch
7. measure for +12v at positive terminal of light-bulb plug

high-beam switch on handlebar only controls high-beams, nothing to do with low-beams. Somewhere between battery +terminal and headlight socket you're losing power. That spot is where trouble is and needs closer examination.