New DRL Bulb Doesn't Work (help)

[dry_heat]

Had my passenger side DRL/Parking Light burn out on me a couple weeks ago (09 135i). Rather than replace with the dealer ($140 for a damn bulb and install!), I opted to order a set of the GP Thunder 7500k H8 35W lights and replace both.

Replaced the burnt-out bulb (and verified that it was the bulb, not something else) and before removing the other one I wanted to make sure this one worked. But it doesn't!

I'm thinking:

A. Need to reset battery before bulb will work?

B. Need to replace both bulbs first?

C. BMWs are finicky.


I did notice that the old bulb was a 36W even though the manual calls for a 35W H8.

Anyone have any suggestions? Car is going in to an indie shop for an alignment in a few days, but I'd love to get this figured out myself so I don't have to pay for this crap to get done.


Thanks!


Side note- anyone else notice that the crappy plastic clips securing their headlights to their car are broken on both units? Because mine are...

[dry_heat]

Bump... No one has any ideas?

[MightyMouseTech]

Originally Posted by dry_heat

Replaced the burnt-out bulb (and verified that it was the bulb, not something else) and before removing the other one I wanted to make sure this one worked. But it doesn't!

How did you verify it was the bulb?

[dry_heat]

Originally Posted by MightyMouseTech

How did you verify it was the bulb?

It was burnt out. Simplest explanation is usually the right one, no?

[ErvGotti]

It's not just the bulb, your ballast might be on it's way out. To answer your questions:

A. No
B. No
C. Debatable

[MightyMouseTech]

Originally Posted by dry_heat

It was burnt out. Simplest explanation is usually the right one, no?

Unfortunately, no. With HID bulbs, less than half the time it is the bulb that is not working. The other half it is either the ballast or the control unit. These systems are a lot more complex than old filament style bulbs. And since an HID bulb does not have a filament, you can't just measure the resistance and see if it is good or not. I usually start swapping parts left and right until I find the part that fixes it.