Rifter rain light sensor issue

I had a similar issue on my Rifter. Do you notice any bubbles forming under the gel pad where the sensor sits on the windshield? Also, have you had any recent windshield repairs or replacements? It might be worth checking the sensor calibration with a diagnostic tool.

Bubbles, huh? I'll have a look tomorrow. The windshield is original, never been touched. What do you mean by 'sensor calibration'?

On my vehicle the delamination of the gel pad resulted in a change in the optical properties of the sensor contact area. The light refraction was disturbed and error messages were displayed. I suggest visiting a professional service center to have the sensor and windshield area inspected, as the rain-light sensor fault may require specific tools for diagnostics and potentially replacement of the sensor's gel pad.

I suspected I would need to go in. Turns out you were spot on - bubbles under the gel pad! They replaced the gel pad, recalibrated the sensor, and now everything's working. Cost me 62€, not too bad!