Weird.

With the bulb removed & the headlight switch on low & the ignition switch on & your voltmeter hooked up to green (ground) and white (low +ve) --- do you get 6+V? (i.e. whatever voltage your battery is at?)

What if you try jumpering directly from the battery to the bulb wires (green and white)? Can you get the low beam to illuminate? (I'd be careful hooking up direct to a charger - some chargers could fry the bulb.)

Maybe there's some corrosion on one of the bullet connectors...?




If the bulb is good there are basically three possible sources of trouble:

 [1] Check the switch - it might need a good cleaning. If you re-pack it with dielectric grease, it'll be basically trouble-free for years.

 [2] If you're unlucky, there may be damage in the switch itself, requiring component or complete replacement.

 [3] If neither of these, it has to be a problem in the wiring in the harness - likely a short somewhere.