squeeeb

i bought a new toyota corolla. the headlights come on automatically and stay on, even though there is the "turn on" handle thing.

two questions.

1: why have a "Switch" if the car is gonna do what it wants when it wants anyway? the lights will come on even if i don't want them on, why tease me with the illusion that i have a choice?

2: lights on don't drain the battery or suck any power, why don't all cars just automatically have headlights on when the car is on, and automatically turn off when the car is off?

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Redlemon

Are they truly "on", or are they "daylight running lamps"?

My Pontiac Vibe came with DLR lights that would change to full-on lights when it got dark. Or when I drove under a tree. People kept checking their rear view mirrors to see why I was brightening my headlights at them.

Turns out that you can disable the auto-change switch easily. Much better now. It is also possible to turn them off completely, although a dealer won't do it because it is considered a safety feature: go to DADRL - How To Disable DRLs for instructions.

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Craven Morehead

I've got that on my car. The switch is useful for when you need your lights on during daylight hours, such as in a funeral procession. On my car, I can also turn the switch to disable the automatic feature. That way if I were parked on a street at night and didn't want my lights on, I could have it so.

I do like this feature, however my wife's car does not have it. Once you get used to it being there you never think about turning on or off your headlights. But then when you get into another car without it,,,,,,,

analog

I'm sure the manual "turn it on" switch is there for times when you should have your lights on but the automatic isn't already on the ball.

I really like the automatic feature, because a lot of morons do not turn their headlights on while it's raining here (first of all, it's the law to have them on if it's raining) and it makes it much harder to see them when it's pouring rain, or even really overcast and misting. This helps eliminate another human idiot factor for other drivers.

telekinetic

The switch is because automation can fail, and it is unacceptable to not have a manual override on a critical system such as headlamps.

Plan9

I drive a newer GM truck. The sensor that detects lights (GM vehicles typically put this on the far right side of the dash) either activate the running lights (ambers) or flip on the headlights when there isn't enough visible light hitting the sensor. This is much like one of those fancy night lights for kids that shuts off when you turn on the bedside lamp, but lights back up when you kill the lights at bedtime.

You have to have manual override ability on high priority systems like lights and doors. While you have a clicker to open your doors, you still have a key slot and inside toggles to lock and unlock the door.

Manual: You can't live without it.

...

I like the switch so I can shut off the OEM light array and kick on the Daylighters.

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squeeeb

redlemon - i'm pretty sure they are "on". i honestly don't know the difference, but they don't get any brighter if i manually turn them on.

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Deltona Couple

As Twisted said, the manual switch is there just in case the automatic lights do not operate. The automatic lights are controlled by a modue. If that module fails, an owner needs to be able to turn the lamps on. Daytime running lights, and automatic lights are a safety feature that makes it easier for others to see your car. Have you ever noticed that durring different parts of the day, mainly morning and dusk, that you missed seeing a car until it was much closer? That is part of the reason for these automatic lights. I am not sure about other makes, but the GM models from about 2000 and newer have a selection on the manual switch to turn off the automatic lights. You have to do this every time you start the vehicle, but atleast then you have the option. Also the switch, if moved to the "running light" position, will turn off the main headlamps.

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MSD

I guess it's convenient, but anyone who can't manually turn on lights shouldn't be driving. DRLs are a drain on the battery, and I read in Car&Driver two years ago that in a 25mpg car, producing that extra electricity is costing you 2-3mpg. When I had a Buick with them, I pulled the fuse after a week and killed them.

THGL

I hate, hate, HATE DRLs.
DRLs are usually the highbeams so they can be seen better during the day. I understand the want for them (so others can see you better) but what I've noticed is that the sensor doesn't kick on the regular lights at dawn or dusk (when it's just dark enough to make high beams distracting or blinding to oncoming traffic). I think just the regular headlights would be a better idea.

My '94 Volvo doesn't have DRLs but it does have the headlight switch switched with the ignition (brilliant idea). Turn the car on and the lights come on, turn the car off and the lights turn off. Basically, I turned on my headlights when I bought the car about 5 years ago and haven't bothered with the switch since.

Back to the original topic... I think the switch also lets you turn on your running lamps w/o the headlights (or DRLs) being on.

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Deltona Couple

How do you figure that they are a drain on the battery? The sole purpose of the battery is to start the vehicle, and regulate the alternator. As far as the person in C&D, DRL's have too low of a amperage use to cause a 2-3 MPG loss. I would like to see factual evidence of a test done to support their claim. It doesn't make any sense what they are saying.

Your information is slightly skewed. DRLs, while using the highbeam BULB, is NOT full power highbeams. They create a series circuit through BOTH higbeam bulbs. This effectively turns on both bulbs, but at HALF brightness. Considering that the standard lowbeam is only 55 watts, and the standard highbeam is 80 watts, then DRL's run at only 40 watts, which is less than a regular lowbeam.

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Plan9

And if I charge my cellphone while driving... my truck dips to 17 MPG.

Huh?

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Leto

I'm the opposite, I love them. In my car ( a Toyota Rav4) they are the high beams with a reduced load. In the old days (th '80's) I would automatically turn on headlights as a good habit, but sometimes forget to turn them off. I noticed that it was not as accepted in the US, where people would come out of their way (in parking lots etc) just to tell me that I had my lights on.

My car doesn't have an outomatic switch over when it gets dark, and I have often driven with my drl's only until I look down and notice that the dashboard isn't lit up.

THGL

We'll have to agree to disagree. Maybe on SOME cars the DRLs are half-wattage high beams, but I know from experience that a number of DRLs I've seen at dawn/dusk are a hell of a lot brighter than another car at the same time with regular headlights on.

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squeeeb

ok, i checked my car, actually, they are daytime running lights, and they are a *Bit* dimmer when they turn on themselves. but as it gets darker, they get brighter and "become" the full regular headlights.

other than the reduced gas mileage they may cause, any reason why all cars just don''t come with automatic lights as a standard package?

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Martian

The two main reasons are the (minimal) power drain and driver perception. A lot of people see DRL's as having dubious benefits and not being worth the additional cost. Personally, I figure if you're that concerned about the 50-80 watts (at the very most) that daytime running lights draw, you ought to be chucking your stereo; aftermarket stereos can draw multiple times that much power and even stock ones in some vehicles are about double the draw.

Colour me as one who disagrees with you as well. American cars that have daytime running lights are usually designed with the Canadian market in mind, since it's mandatory on all new vehicles up here. Federal regulations specify that daytime running lights cannot have a luminosity greater than 7000 candela, which is significantly lower than the 75 000 candela limit placed on high beams or the 65 000 candela of low beams. As noted, this is most commonly achieved by wiring the high beams in series and thus effectively halving the wattage (the regulations were specifically amended to allow this design; originally they called for a much lower intensity, but that was to avoid requiring automotive manufacturers having to include a seperate system specifically for the daytime running lights).

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