Automatic high beams problem

[paul_alfred]

I have a 2019 RC350 F Sport. Last night during a 3 hour drive my automatic headlights would occasionally dim, as they should, but then the "auto" indicator would turn off, and the headlight would stay in low beam mode, would not return to high beam mode, and the stalk would not operate.

When the "auto" switch was engaged and the "auto" indicator light turned off, and another cars headlights approached and passed by, the "auto" indicator light would come on again and the headlights would return to normal "automatic" mode operation, for a while.

This happened perhaps 6 times during the trip.

Pressing the "auto" control switch would disable automatic dimming but would leave me in manual headlight mode which operated normally.

The dealer tested the car and couldn't find any problem but it recurred again shortly after leaving the dealer this evening. Of course they tested in the daytime when it is impossible to duplicate the issue...

As I was about to turn around to show them the issue, the auto light came back on and the problem disappeared, again.

I hope this isn't too hard to follow.

Does anyone have any idea why this would happen?