VW Rain Sensor Failure Triggers Multiple Electric Glitches

As someone with moderate experience working on VWs, I had nearly identical issues with my 2015 VW Transporter TDI. The rain detection system and other electrical gremlins pointed to the same root cause you are describing. After diagnostic testing, the workshop found bubbles had formed under the gel pad connecting the rain sensor to the windshield. This caused intermittent sensor fault readings and triggered multiple electrical issues similar to yours. The fix involved carefully removing the old sensor pad, cleaning the contact area, and installing a new gel pad with the sensor properly realigned. Total repair cost was 62€ and took about an hour of labor. Before offering more specific advice, could you share: Has the windshield been replaced recently? Are the issues more frequent in hot weather? Does the malfunctioning sensor behavior change when driving through tunnels or under bridges? Have you noticed any condensation around the sensor housing? These details would help determine if your electrical fault stems from the same sensor connection issue I experienced. The rain sensor system in these VW commercial vehicles often shows similar failure patterns when the mounting deteriorates.

I had my last service at 171000KM and can confirm the issues started appearing gradually over the past 2 months. The windshield is original and has never been replaced. The auto sensor issues definitely get worse in hot weather and when moving between bright sunlight and shade. No visible condensation around the light sensor housing, but I notice the automatic functions completely fail during heavy rain. Your experience matches my symptoms exactly. The malfunctioning sensor seems to trigger unusual electrical behaviors, especially with the auto wipers and lights. I will have the workshop check the gel pad connection, that could explain why the rain detection stopped working properly. The 62€ repair cost sounds much better than the 400€ estimate I received. Did you source the gel pad through VW or find an aftermarket option?

Thanks for those additional details about your Crafter. The symptoms you describe are textbook signs of a deteriorating sensor gel pad, nearly identical to what I experienced. The hot weather sensitivity and erratic behavior when transitioning between light conditions strongly point to the gel pad connection issue. The car electronics are getting inconsistent signals because the rain sensor and light sensor cant maintain proper contact with the glass. I opted for the genuine VW gel pad which cost about 15€. While aftermarket versions exist for around 8€, I found reviews indicating they often fail within months. The installation labor makes up most of the 62€ total cost. A repair tip from my experience: Make sure the workshop thoroughly cleans and degreases both the sensor housing and glass contact area before applying the new pad. Any residue can prevent proper adhesion and lead to premature failure of the rain detection system. The fact your issues developed gradually over 2 months rather than suddenly appearing also matches the typical gel pad degradation pattern. At 171000KM, this is a common maintenance item for these sensors. Would definitely avoid paying that 400€ estimate, the repair is straightforward with the right parts and proper installation technique. The entire sensor rarely needs replacement unless physically damaged.

Based on your feedback and that 62€ cost comparison, I will definitely pursue the gel pad replacement route first. The matching symptoms with the rain sensor and other electrical issues gives me confidence this is the core problem. I will contact a few other workshops and specifically ask about their experience with rain detection system repairs on VW commercial vehicles. The sensor calibration process seems straightforward enough that any competent shop should be able to handle it. For now, I have been manually operating the wipers and lights to work around the faulty sensor readings. Will book the repair next week and make sure they use a genuine VW gel pad for proper rain sensor function. The thorough cleaning tip is especially helpful, I will make sure to mention this to prevent any sensor fault issues from returning. Really appreciate the detailed repair advice and cost guidance. This saved me from potentially overpaying for unnecessary component replacements when a simple gel pad could resolve these auto sensor problems.