What are the larger headlights for?

[dm567]

OK, this may sound stupid and probably is but I can't figure out what the larger of the two headlights is for. It only comes on when I hit the momentary high beam. The smaller headlight on my 2004 x5 that is a xenon unit provides both the low and high beam. I just posted my version of the "how to" replace it.

I never would have even looked but the low beam went out. I always thought the big one was high beam and the little one low beam?

What are the larger headlights for?

[MINIz guy]

You have bi-xenon headlights. When your low beam is on and you need to use the high beam, a shutter opens up and allows more light to pass through the xenon projector.

However, when your low beam is off, the shutter will be of no use since the xenon bulb is off. That is what the larger headlight is for -- when you need to flash your high beam with the low beam off. The car cannot turn on the xenon low beam and open the shutter for quick high beam flashes as the xenon ballasts needs a second or two to heat up -- a quick on/off of the ballast would harm it.

[RickM5X3]

Originally Posted by dm567

OK, this may sound stupid and probably is but I can't figure out what the larger of the two headlights is for. It only comes on when I hit the momentary high beam. The smaller headlight on my 2004 x5 that is a xenon unit provides both the low and high beam. I just posted my version of the "how to" replace it.

I never would have even looked but the low beam went out. I always thought the big one was high beam and the little one low beam?

What are the larger headlights for?

In theory, one of the uses is 'flash to pass,' where you pull the headlight stalk towards you a couple times for a friendly signal for someone ahead to move right. But I wouldn't advise it, as you are likely to be flipped off, brake checked, shot or worse.

[Phr3d]

also Daytime Running Lights, though I do not have a bi-xenon to test and see if the xenons can run at 1/4 light for that function.

I have been very fortunate in never having someone do a brake check when I flashed to pass the myriad left-lane bandits.

[Gixxerboy63]

Originally Posted by RickM5X3

In theory, one of the uses is 'flash to pass,' where you pull the headlight stalk towards you a couple times for a friendly signal for someone ahead to move right. But I wouldn't advise it, as you are likely to be flipped off, brake checked, shot or worse.

It seems that the rest of the world understands this courtesy, but unfortunately, ignorance and narcissism has become the rule here.

[pezho405]

Yeah at night i always play with them, like its annoying because i think the halogen hiughbeam is better at lighting up stuff than the xeon....but i love having them like to flash them and stuff.

[motordavid]

Originally Posted by RickM5X3
In theory, one of the uses is 'flash to pass,' where you pull the headlight stalk towards you a couple times for a friendly signal for someone ahead to move right. But I wouldn't advise it, as you are likely to be flipped off, brake checked, shot or worse.

Originally Posted by Gixxerboy63

It seems that the rest of the world understands this courtesy, but unfortunately, ignorance and narcissism has become the rule here.

+1, Good posts, but unfortunately true, here in the US...

[Helmuth]

you still can do that here in Europe .... if you have an X5 .... that is still an argument here guys :-)
Of course 911 Carrera GT3 would be a better one but X5 works too....

[Gixxerboy63]

Hey Motordavid, I was checking out your flicker photos. I saw some stucco architecture with tile roofs and there were even a few funny looking trees showing up in your background.... is that unique to western NC?

[motordavid]

OT...

Originally Posted by Gixxerboy63

Hey Motordavid, I was checking out your flicker photos. I saw some stucco architecture with tile roofs and there were even a few funny looking trees showing up in your background.... is that unique to western NC?

It's our FLA Starter Shack. I was pizzed I couldn't get palms to grow at our Mtn Joint, at 5,000 ft elevation, and in Zone 5a...

Sharp eye.