The other day, I had a 3 hour drive after dark, in rain and light fog. Most of the driving was in another section of BFE, and was using the auto settings on the heads.
Found out that the heads would automatically go to the lo beams when hitting the fog. I don't think my Morimoto Hybrid XB's had anything to do with it, but rather the sensor picking up reflection of the fog.
Thought it was a nice feature I wasn't aware of.
Anyone else notice this, or is it really a side effect of my aftermarket heads?

 

The auto headlights function working exactly as it is supposed to, i.e. going to low beams when it senses light, i.e. the reflection.

 

As said, that's what I was thinking. Kind of a neat little extra.

 

Fog means moisture -here in CA there has been very little moisture since I've only my truck (late 2019).
I do recall a situation once where the system was a little confused, could have been foggy!
But yes, I too have in fact experienced it once or twice in the past.
It's been tripped up too from some road signs, like a speed limit sign...... must have had a good angle on it to reflect back.

 

Better check
All vehicles in the US were set up to turn off Fogs or running lights when Hi Beam turns on from the factory, by Law more than 25 years ago.
My 2018 in regular switch position turns the driving lights off on Hi Beam setting. It's not automatic acting but wired that way by relay.
That function is also by state Law, here in my state. It states the driving lights cannot be on with Hi Beams and an inspectable item.
I see too many who changed the driving light lamps to very high intensity, have no focus and blind oncoming vehicles. Seems they never pay attention to what happens with such a lamp change. Some are even brighter than the head Lites. Not good!
I don't use the DRL setting.
I have a 90 Lincoln with auto dim and driving lights under the bumper from the factory that also turns off the driving lights on Hi.
Easy to check. Turn em on, change, and take a look in daytime.

 

@johnday in BFE I was actually thinking of you earlier today, wondering how you were liking those XB's?

 

I really like them, best headlights I've ever had on a 150. I did try the planks to be on with the truck, but they were too bright, pulled the fuse, and just use the dimmer light that comes on with the lights.
I don't get glare and scattered light anymore either, much more focused.