2G High beams don't work, headlight wiring problem?

[newtypedsm]

i was trying to figure out why my high beams seem to not work (hardly any difference between low and high) and i was checking the voltage to the wires when i noticed there is power, not much, but some going to the high beams when the low beam is on and no power at all when the high beams are on but full power is supplied to the low beam no matter which light is engaged.

 

[luv2rallye]

Assuming you don't have the "daytime running light" option (non-US I believe), either your high beam filament is bad or wiring to the high beam is faulty or the most likely case is your dimmer switch is bad.

Both high and low are turned on by grounding one side of their filament. The other sides are common (connected together) and connected to +12v when headlight relay is on. So with just low beam on (+12v on one side (common one) and ground on other), the non common high beam filament side is not connected to anything (it floats). Therefore you will read +12v on it because it is connected to +12 through itself (it's own filament to the common - no current flows so it just acts as a wire). When you try to turn the high beam on, it is not getting a ground on it's non common filament side for some reason so it doesn't turn on.