On my 991S when the headlight switch is set to auto, the lights don't always turn off when I go from a dark place to daylight. It seems to happen in overcast conditions and not in bright sunlight. Is there a way to adjust the sensor to correct for this? Or maybe I just have a bad light sensor?

 

it depends upon the duration of low light.
mine always goes on when i pull into the garage.

I suggest that you monitor it....there is no adjustment.