Nina's Blog - Saturday 28th February 2026

Saturday 28th February 2026, 13:55

The whole journey to Tønsberg and the Vaffel og Vintage charity shop was foggy, mostly foggy enough to warrant rear fog lights. So autosteer wouldn't engage. The amount of fog we've had over the last couple of days is quite unusual so I'm uncertain how well it worked before under similar conditions.

But once the fog cleared the autosteer started working again.

Unfortunately there's a potentially more serious problem. A few seconds after I start driving the steering was suddenly heavy and a warning appeared in the instrument cluster saying that steering assistance was reduced. It only lasted a few seconds but that's worrying enough to be worth getting checked so when I get home I'll book it in to Tesla.

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ArishMell · 70-79, M

The auto-steering problem...

I think you mentioned elsewhere it uses a camera. I wonder if in fog water can collect on the outside of the lens, blurring the image enough for lost definition. All the more so if a faint layer of normal damp-weather traffic grime is on the lens, to nucleate the water on its particles. A similar effect to what happenes if we try driving into the sun with a dirty or greasy windscreen.

ninalanyon · 61-69, T

@ArishMell

I wonder if in fog water can collect on the outside of the lens

Not really. The lens is on the inside of the windscreen in an area wiped by the wipers. It works fine even in pretty heavy rain as well as intermittent rain when the windscreen wipers don't trigger immediately to clear it..

I think the problem is one of limited dynamic range and low light sensitivity. It's a monochrome camera from quite a long time ago, probably not state of the art even when it was installed over ten years ago. It's easily dazzled by driving toward the sun this far north, not a problem when I'm driving in Europe and very rarely in the UK but here when the sun might be only 15 degrees above the horizon at midday with snow on the ground reflecting light it's rather more challenging. I think the situation with fog is similar except that instead of there being too much light in one spot it is all spread out and the limited intensity resolution of the camera can't pick features out of the low contrast image.

ArishMell · 70-79, M

@ninalanyon I fitted a reversing-camera to my car, and that is very easily upset by dirt on the window or dazzled by lights shining towards it. It might be better if I move it from inside the rear window to outside, which I think is intended.

ninalanyon · 61-69, T

@ArishMell The reversing camera on my Tesla is on the outside and it gets dirty very quickly. I have to clean the lens pretty much every time I get into the car in the winter. I wish it had some kind of washer or wiper.

ArishMell · 70-79, M

@ninalanyon That's why I fitted mine inside the rear hatch window, but although it does work there it is prone to optical problems, including some loss of definition by having to "look" through thick glass at an oblique angle.