Falcon rain light sensor fault

That sounds frustrating. I had something similar happen with my old Audi, though it was a different sensor. The symptoms you're describing—especially the seemingly random light activation—could point to a wider sensor fault. Have you checked the sensor calibration? Is it correctly detecting moisture or ambient light? It could also be a ground issue somewhere in the harness.

Thanks for the quick reply! Regarding the sensor calibration, how would I check that myself? Is it something that requires specialized tools, or is there a procedure I can follow? Also, where is the best place to check the earthing?

With my Audi, checking the calibration involved a VAG-COM tool, so it's likely you'll need something similar for your Ford. The earthing can be a pain to locate, but check the body near the sensor first and foremost. Given all the symptoms, though, and unless you're very comfortable with diagnostics, I'd suggest taking it to a workshop. They'll be able to pinpoint the exact cause of the malfunctioning sensor.

Thanks again! After taking your advice, I took the car to the workshop and they confirmed it. The problem was bubbles forming under the gel pad of the windshield. They replaced the gel pad, recalibrated everything and now it works as expected. The final repair cost was 62€. Thank you for your assistance!