Originally Posted by Boatman
Possible you have a broken filament inside the bulb and it's shorting the hi/lo together. My next step would be to test the feed with a test light at the bulb connector.
But how can it be possible? The hi/low bulbs are separated and there is one thread in each bulb... And both bulbs are working, when the bypass trigger and hi beam switch are activated togeter...
Dirt in the off/parking/drive light switch. Driving light position was corroded and covered with dust after last offroad ride. Simple solution.