Why do Headlights Stay On When Ignition Off?

[Music Lover]

I've always had the opposite question. Why don't car headlights automatically come on when the car is started? And then they could stay on for a minute or two after turning the car off, then shut off automatically. As a safety feature it seems it would be cheap and easy. It doesn't drain the battery to have them on when the car is on.

And my second question: why don't the lights come on automatically when the windshield wipers get turned on. Many (most?) states have a law that when the wipers are on the lights should be too. Again, it seems like it would be an easy and cheap method of increasing safety.

Daytime driving lights are mandatory in Canada, rain or shine. Now that most if not all cars have LED lights that use little power and probably will never burn out, I don't see any reason why that can't be a standard feature.

Regarding headlights turning off, my car (Acura) has 3 options: on, off, or auto. I can also select how long they stay on after the car is turned off from 0 seconds to 60 seconds.

 

[Andre1969]

I suspect that in the "early days" pre-1980ish it was one less thing to go wrong by leaving a switch out of a safety item circuit. Faced with headlights that don't work when needed and a need to go home right then, most [-]idiots[/-] people will drive home anyway thus endangering themselves, which is okay if they want to, and everyone else, which is not okay.

That's probably just it...simplicity. As time went by, they started making the cars more idiot-proof. For example, in 1968, you could hop in any new car on the market and slip it into gear, and turn the wheel, without the key. It wasn't until 1969 that GM put the first locking steering column/gearshift in a car (domestic cars, at least). Chrysler followed suit in 1970. I think Ford did as well, but I'm not sure. I think the goverment mandated it for 1970

However, on cars with a floor shift, you could still shift it into gear without a key. I had an '88 Chrysler LeBaron turbo coupe that was like that.

At one point, power windows were also hard-wired, just like your cigarette lighter or headlights. I don't know what year that changed...probably sometime in the 1960's. I know I've seen a 1959 DeSoto Fireflite that had power windows that could be operated without the key. My guess is that either a kid rolled the window up on his brother's head, or too many kids just played with them, unattended, and ran the battery down, and the government stepped in and said to the auto makers, no more!

Headlights were probably one of those things where, eventually it got to the point that the auto makers simply started designing the systems to where the lights go off automatically after something like 15 minutes, if you forget and leave them on, just like interior lights tend to do. Those types of features tend to get introduced in higher-end models first, but eventually trickle down the ranks, to the point they become expected standard equipment on everything. And in that period of the late 1990's/early 2000's, that's probably when a lot of that trickle-down, with regards to headlights, was happening. The government mandate of DRLs might have had something to do with it, as well. Since the headlights, or some form of light, had to come on automatically, easy to just make it turn itself off automatically, as well.