I could see the problem being a few things:
1. Sounds like one of the resistors may have failed. You could remove the bulb, and if anything is melted/burnt/charred, then there's a possibility it is due to a blown resistor.
2. Perhaps the bulb has become lose. Try unconnecting and reconnecting it.
If reconnecting doesn't work, then you need a new bulb. HighPerformanceBulbs.com, ModMy3, e92-Lighting, etc. all offer canbus domes.