I have a 2003 Cooper S with halogen lights (using Sylvania SilverStar H7's). I replaced a left low beam two weeks ago and noticed yesterday it had burned out again so I replaced it. Today it's burned out again after less than an hour's use. What could be the cause of this? The connector looks OK and it's not a fuse. Is there something that could cause a voltage spike to fry these things or another cause?

 

You cannot touch the glass bulb with your fingers when you install them, the oil from your fingers combined with the high heat of the lamp will cause the bulb to fail.

If you do accidentally touch the glass, clean it with isopropyl alcohol and a cotton ball.

 

The bulb glass was never touched and I use nitrile gloves when installing them

 

Update: I checked the bulb I replaced that I thought was burned out with a 12V source and it still works. The replacement bulb still in the car that quit working yesterday now works, at least for now. I hate these intermittent problems.
The lights go thru the General Module Control Unit (boy, that sounds expensive!) and according to my Bentley manual you can access the Module trouble codes thru the OBD II connector. I checked with my Peake scanner and found no faults but I think the Peake is mostly engine related fault finding, not lighting, so I may have to (Gulp!) take it to my dealer. Anyone else experienced this problem?

 

Update 2: Problem Solved; loose connector. Took a little screwdriver and deformed the metal a bit to increase the friction. I guess slamming the hood has taken its toll over the years.