Mini Roadster rain light sensor fault

Interesting problem you've got there with the Mini Roadster's rain-light sensor. Sounds eerily familiar. I had a similar electrical fault situation with my old Peugeot some time ago. Symptoms were nearly identical – error codes, malfunctioning automatic wipers and headlights, the whole shebang. Have you by any chance inspected the rain sensor module itself? Is there any visible damage, moisture, or corrosion?

Visible damage, you say? Where exactly should I be looking on the rain sensor? Any tips on getting to it without making things worse?

Right, accessing the sensor can be a bit fiddly, so proceed with caution. On my Peugeot, the sensor was integrated into the base of the rearview mirror, stuck to the windshield. Check if yours is similar. As for the 'bubbles', those form between the sensor and the windshield, interfering with rain detection and light sensor readings. Honestly, given the symptoms, it does sound like that's your culprit. But is it DIY fixable? Perhaps not. I'd advise consulting a qualified technician to avoid further complications with the car electronics. It's a sensor fault, and electrical faults can be tricky.

Just wanted to update you, mate. It was exactly what you suspected! Bubbles under the sensor's gel pad. 62€ later and she's good as new. Cheers for the insight!