My car has an automatic setting for the headlights, so that they automatically (thus the automatic part) turn on when it gets dark. Cool! So I have the lights set on automatic; no one can say that I am not a product of our times!
I noticed, however, that towards the end of the day, when it is not really dark yet, that the lights will flicker on for a few moments when I pass under a bridge or go through a shadow. Is this momentary flickering killing my headlights? So far I haven’t had to replace a bulb, but the car is fairly new…
There probably is a bit of extra wear on the bulbs but I’d expect it to be minimal
Mine are the same but they don’t flicker, they stay on for about a minute after re-emerging from a tunnel or a shady avenue of trees.
Maybe the threshold on your sensors is set too close so they are “hunting”, or the timing circuit wants tweaking - probably a dealer service as it will involve resetting the onboard computer(s)
Mine don’t even kick on until after (I’m guesstimating here) about 30 seconds. And then they stay on for at least a minute after coming on. So, no troubles with overpasses. I’m on the original lamps that have to be 7 years old now.
I have had three Toyotas with auto lights and none of them do this. Lights shouldn’t flicker at boundary conditions. I believe that engineers design the switches to avoid that. A EE told me once you have the same situation with thermostats, and there is a stasis loop built in to avoid frequent cycling on and off when temperature is at the boundary.
I have auto lights on my Mazda3, but I wound up not using the auto setting because any time I turned the key on at night the lights would come on. Annoying.
To each his own, but… that’s the point. I’m missing something that’s particular to your circumstances. My lights don’t come on when I key to "ACC"essory position; but only in the ignition/run position. Which is when you want them to be on, you know, when it’s night.
I’m pretty sure mine came on in ACCessory position, so I couldn’t sit and listen to the radio or whatever without my lights being on. Or I couldn’t turn the ignition on to roll up/down my windows without the lights coming on.
I do like my auto wipers pretty well though, saves a lot of fiddling with the wiper speed on misty days.
I have a WAG. Do you have driving lights? My Chevy truck has driving lights and when it gets dark the actual headlights turn on and the driving lights turn off. Could that be your flicker?
Nope, no driving lights… it is the headlights that come on. However, reading the replies in this thread has made me second-guess myself: are the lights flickering, or are they turning on for 30 seconds or so, and I’m just noticing when they actually turn off and thinking that they flickered? I’m going to have to watch that for the next day or so to see.
I’ve always heard and used the term hysteresis loop to describe this approach. There is some difference (deadband) between the activation and deactivation points. Also referred to as 2-position control with differential, but hysteresis is shorter.