VW Caddy Rain Sensor Failure Causing Multiple Issues

Had a similar issue on my 2012 VW Golf with the auto sensor system completely failing. The symptoms were identical, no automatic wiper response, light sensor malfunction, and erratic dashboard behavior. The root cause turned out to be moisture intrusion through the windshield seal around the rain detection unit. Water had corroded the electrical connections and damaged the sensor calibration system. The gel pad that connects the sensor to the glass had developed air bubbles, compromising the entire rain sensing function. The repair required: Complete removal of the old sensor unit, Cleaning of the electrical contacts, Installation of a new sensor module with fresh mounting gel, Full electrical fault scan and reset, Sensor calibration after installation This was not a quick fix, the entire assembly needed replacement since the internal components were damaged beyond repair. The electrical fault also affected other systems due to shared connections in the comfort control module. Worth noting that these auto sensor problems often indicate early stages of seal failure. Getting it fixed properly prevents more extensive electrical issues developing in the comfort and safety systems. Best to have this addressed by a shop with experience in VW electrical systems, as proper sensor calibration requires specific diagnostic equipment.

Thanks for sharing your experience with the Golf. Pretty much matches what happened with my Caddy last spring when the rain sensor started acting up. Those malfunctioning sensors can really cause a chain of electrical gremlins. Quick question, do you remember roughly how much you ended up paying for the complete fix? Also, has everything been working properly since the repair? Just want to get a sense if I should expect any follow-up issues with other car components once I get the sensor replaced. My mechanic suggested similar steps but knowing another VW owner had success with the full sensor replacement gives me more confidence in going ahead with the repair. Just trying to budget accordingly since these electronic fixes can get pricey.

Got good news to share, after getting the repair done exactly as described earlier, everything has been working flawlessly with the auto sensor system. The total cost came to 62€ to fix those troublesome bubbles under the gel pad. The light sensor and rain detection are now responding perfectly, and the dash displays are back to normal. Most importantly, the sensor calibration process they performed seems to have completely resolved the original fault code. No moisture issues or electrical problems have popped up since the repair. The car electronics are all communicating properly now, and the auto functions work just like they did when the car was new. This kind of targeted fix focusing on the gel pad adhesion issue typically prevents any cascade of problems into other systems. The key was addressing it before moisture could cause more extensive damage to the sensor connections. You should see similar results with your Caddy since it uses comparable sensor technology to my Golf. Just make sure they do a proper calibration after installing the new components.

Thanks for the input. Finally got my Caddy fixed last week and wanted to share how it went. After seeing these responses, I took it to a specialist who really knew their way around VW electrical systems. Turns out the rain sensor was completely shot, just like yours. The mechanic found corrosion around the mounting area and those same air bubbles in the gel pad you mentioned. Total bill came to 580€, more than I hoped but less than I feared. They replaced the entire sensor unit, cleaned all connections, and ran a full system calibration. The auto wipers and lights are working perfectly now. Plus, those weird dashboard glitches cleared up right away. The mechanic showed me how the old light sensor was basically toast, looking at it explained why nothing was working right. Best part is they found and fixed a small leak in the windshield seal that was causing the original moisture problem. Should prevent any repeat electrical fault issues down the road. Really glad I got this sorted before winter. Having working auto wipers and properly functioning sensors makes such a difference in bad weather.