Auto Headlights Inconsistent?

[SkiDooNick700]

Hey all. Anyone know how exactly the auto headlights work on these trucks?

 

On a sunny morning (7:20-7:50am ), my headlights will cycle On and Off 6 to 7 times (counted multiple times recently) on my 20 minute commute to work. Only one of these cycles is due to a tunnel, the rest are due to the suns position and how what I am guessing is it casting a shadow over the dash area? It just drives me nuts. First thing I do in the morning now is just take control of the lights by turning the knob to the "off" position, you know, which I kind of hate doing because I love the SLT DRLs!!

 

Now here's what is interesting. On a cloudy morning, like this morning, my headlights do not turn on a single time. Rarely do they turn on in the tunnels on a cloudy day!!

 

One last thing, on my commute home, around 4:30 in the afternoon when the sun is still up in the sky, my auto headlights kick on thru the tunnel, within seconds, and then seconds after that I'm out in the bright sun again, yet it takes a little over a minute (travel over 1 mile at 60mph) for them to kick off again.

 

I guess it is what it is and I should probably just let them "do their thing" like 90%+ of the other drivers out there. Problem is, I am not that 90%

 

 

Can the auto headlights be "tricked" into thinking its always day time? I believe this was possible on the older trucks. What would really be best for me is if there is a way to keep DRL on even when you turn off Auto Headlight control.

[LongrangeLauber]

You could cover the sensor in the middle of the dash and it will always think it's dark. My hat will sometimes slide over top of mine and dash will get dark and lights come on even in the middle of the day

[SkiDooNick700]

Right, I understand that. I think what I am trying to get at here is why is it on a sunny morning the sensor keeps going from day to night as opposed to a cloudy morning where it always thinks its day.

 

Maybe the cloudy days have a more consistent ambient lighting as opposed to sunny days where depending on how it hits the cab it causes a shadow or something.

[kp52]

I the sun is behind you the lights will stay on quite a while in the daylight, if I drive west in the morning and I start out at dawn the headlights wont turn off at ll even though its bright and sunny out. Going east they turn off as soon as the sun comes up. On cloudy days they will turn of earlier, most likely because there isnt a strong shadow on the sensor, who knows.

 

Maybe somewhere in GM wizardry if the sun is behind you the headlights stay on so oncoming drivers getting glared by the sun can see you better. Most likely its just the position of the sensor and thats just the way it is. Older cars used to have a sensitivity adjustment, but not much you can really do except turn them on and off manually..

[Thomcat]

They called it a Sun sensor in my 300M and that system was really screwed up.....if the Sun flickered through overhead tress onto the sensor, the automatic lights would turn on and off in a frenzy.

 

Appears the GM version gives more weight to rapid response time if it can "see" the Sun rather than a delayed response to the same overall brightness level if the Sun is not directly visible by the sensor.......something like the spot meter taking precedence over the area meter in a camera. A small piece of white paper over the sensor, thin enough to let light pass through and thick enough to diffuse the hot spot of the Sun, essentially acting like a cloud cover, might help to even out the response.

[Kyle919]

Could be a brightness difference. There is a big difference from going to bright and sunny to a tunnel. Not a big difference going from cloudy to a tunnel. Could just be how the sensor is picking up the light change.