Latitude rain sensor fault

Sounds familiar. I've got a Latitude too, and had similar issues with the rain detection. Is there any chance you've got bubbles forming under the gel pad on the windshield where the sensor sits? That can mess with the light refraction and cause all sorts of electrical faults. Does the rain sensor work at all, or is it completely dead?

Bubbles under the gel pad, you say? I'll have to take a look. Where exactly should I be looking? And if that's the case, is it a DIY fix, or am I looking at a trip to the shop? Is a sensor calibration needed?

Yes, check the area directly behind the rear-view mirror on the outside of the windshield. You will see some kind of bubbles there. While some people attempt DIY fixes, because of the error stored, I'd advise against it. The issue requires specialist tools and a good knowledge of electrical systems. Also, keep in mind that a malfunctioning sensor also affects the speedometer dimming. It will probably be cheaper and more reliable to get it professionally checked.

Thanks for the insight! It turned out to be exactly as you described: bubbles under the gel pad. Took it to a local shop, and they replaced the gel pad. Cost me 62€, and everything's working perfectly now. Much appreciated!