Does Anyone Leave Their Headlights On?

No, it wouldn't shorten the life of the bulb in "hours" as much as it would compared to the life of the car. Usually lights are used in inclimate weather and night time (including dusk/dawn) conditions.

Consider maybe 30-50% of the time at most you drive at night. (a high estimate for most of us)

Let's use 40mph as a constant for speed since it's a mix between city and highway.

HID bulbs have an average rated life of 3000 hours (somewhere in there). At 40mph, that's 120,000 miles full time. At 50% usage, we're looking at double that.

Halogen bulbs are rated between 320-1000 hours. (per sylvania's site). That's 12,800 to 40,000 miles full time. At 50% usage, that'd be 25,600-80,000 miles.

Regular bulbs don't cost that much, and aren't generally harmful for the environment.

HID bulbs, however, must be properly disposed of due to their mercury content, and dealer replacement would run you a few hundred bucks.

Another note about HID bulbs, they grow dimmer over their useful life, and the color temperature changes as well.

I don't run mine all the time in my '04, however my '02 is equipped with DRL's (which run the low-beams at reduced power to increase bulb life). I would have chosen DRL's as an option on my '04 had they been available, however only on the premise that they're not as intense as night-lighting - to discourage their accidental use. I wouldn't mind converting my fogs to be DRL's if such a kit were to become available.

hope this helps,
-Rick

 

Nope, it's one of the "documented features" that never quite made it into the production car.

 

Sorta correct. Cars equipped with Daytime Running Lights are also equipped with the Automatic lights feature. This is helpful so that you don't drive around w/ only DRL's on at night.

The problem is, DRL's aren't possible on HID cars as presently configured, so we didn't see the automatic headlights in the US as DRL's simply weren't an option.

Our Canadian friends, however, have laws which require DRL's, so they get them plus auto headlights, but no option for HID lights as a result.

hope this helps,
-Rick

 

The only disadvantage with that is that there is a miniscule power draw associated with keeping that "circuit" active. I wouldn't do it over a period of a week or more.

 

I'd love the fogs to be on via the DRL relay (one would have to be installed, assuming the harness is there for it).