Q: 2004 CADILLAC SRX replaced low beam headlight bulb but it still doesn't work. someone said the baluster may need to be replace.

High-intensity discharge, or HID headlights require a lot more voltage to light than conventional halogen bulbs. Then once lit, they consume less wattage than the halogen bulbs. Sometimes referred to as a ballast or ignitor, this component amplifies the 12 volts provided by the vehicle’s electrical system to roughly 40,000 volts to initially light the HID bulb. When ballasts go bad, the light may flicker or not light at all. Typically the ballast is part of the headlight and not available separately, usually requiring replacement of the entire headlight but this varies from vehicle to vehicle. You may be able to find a replacement ballast independent of the headlight either through a dealership parts department or shopping online. Either way, replacing the ballast will require removing the headlamp assembly for access. The front bumper cover will have to be removed in order to remove the headlight.