So I've had my HID setup surprising for a long time but today it just went out. When I turn on the headlight usually there's a humming sound but on the passenger there's no sound. There's still sound from the driver side. I want to say the bulb has gone out but I don't want pull the front bumper until I know it's either the ballast or the bulb. Anyone?

 

Switch the bulbs from one side to the other.

 

That's the sound of the bulb heating up. 9/10 times the bulb needs to be replaced..... From my experience. Only way to tell is to swap parts as stated above.

 

Yeah I swap the ballast and the headlight came on! I kinda had a feeling it was the ballast. Lesson learn no humming sound=bad ballast.