I've been having intermittent issues with auto dim rear view & door mirrors. The headlights glare at night doesn't seem to be reduced and when pressing on/off on the rear view mirror with yellow LED turning on/off I see no difference...other times it seems to be working. This feature worked flawlessly in my BMW and on Lexus.

Has anyone else experienced similar issue and if yes, how Porsche service fixed it? I'm worried if I take up there it's going to behave --I hate these intermittent issues!!!

 

Is it all three mirrors or do your side mirrors dim properly.
If it's all three it must me a loose connection.
Does it have its own fuse?

 

It's all 3......

 

Not sure if it works on the 991, but you can usually check the self-dimming system when you trick it by putting your finger on the light sensor at the back of your rear view mirror. The mirror believes you are driving in the dark and will start dimming because of the daylight hitting the mirror.

If this trick works on the 991, you can do it several times over the next few days and check if the mirror operates consistently.

 

Sounds like one of the two sensors malfunctioning? A new mirror under warranty?