I have just installed passing lights to my 73 FL Shovelhead. Wired them according to schematic. The main head light dims when passing lights are turned on. Must go to bright to get passing lights working. When not ob "bright" the passing lights have only minor voltage to bulb. Any ideas of what I did wrong?
Thanks

 

Weak wiring , the stock harness is only like 18 gauge for the head light and the handle bar switches aren't big enough to take the load if you wired them to work off the hi/low switch unless you ran them through an add on relay . I always run a separate toggle switch for passing lights with 12 gauge wire , the old bikes didn't have the amps the new hi wattage lights need

 

Thank you for the words. I was heading in that direction and you confirmed my idea.