Omega Xenon Problem, any automotive sparks out there?

[pacman1]

As the title suggests, I have bought a Vauxhall Omega fitted with D2S 85122 xenon headlights.

The car came with one headlight not working, Phillips fitted.

I purchased a pair of non OEM ones from the bay of fleas. Packaging was poor, with one of the plastic protectors fractured. I have informed the seller of this via feedback.

However, I tested both bulbs and they work, so I fitted one. I noticed a minor hum from inside of the car which wasn't there before.

The bulb lasted a day before it failed and the hum has now gone.

My next move, before I contact the seller, is to swap the orginal working bulb from the other side over to this side and fit the remaining good bulb in it's place. If it blows on the same side again, I can probably rule out the bulbs themselves being at fault.

If it turns out it is not the bulbs at fault, could someone point me in the right area as to what might be causing them to fail on the one side, a ballast resistor maybe? If it is indeed something else, then maybe I can fix it before I blow any more bulbs!

Thanks in advance chaps.

[stevieturbo]

Obvious thing to replace would be the control unit/Ballast. Be quite a bit more expensive than just the lamp though.