T-Roc Defrost System Failure: Heating Coil Problems

I had a similar issue with my 2021 VW Tiguan last winter, and from my moderate experience with car heating systems, this sounds very familiar. The main problem turned out to be a heavily discharged battery that was no longer providing enough power to run the thermal window elements properly. The auto defrost system requires significant electrical power to function correctly. In my case, the workshop first tested the battery capacity and found it was only operating at about 40%. They also checked all heating coil connections and the window heater relay. After a complete diagnosis, they determined the battery needed replacement to restore proper function to all heating elements. The total repair cost was 290€, which included: Battery diagnostics, New battery installation, System testing, Heating circuit verification Before I can provide more specific advice about your situation, could you share: How old is your current battery? Are you experiencing any other electrical issues? Does the problem occur more frequently when starting the car? Have you noticed dimming headlights or slow engine cranking? These details would help determine if your T-Roc is facing the same underlying battery issue that affected my Tiguan.

Just had my car serviced last week at 146733km and they did a full electrical check. The battery is only 8 months old and shows normal voltage readings. The defroster repair might be more complex than a battery issue since both front and rear window heater systems fail simultaneously. The heating elements appear to receive power but do not warm up properly. The error light persists even after clearing the codes. When testing with a multimeter, the rear defroster shows inconsistent resistance readings across different sections, suggesting possible damage to the heating grid. The front windshield also stays cold even when the system is activated. Has anyone dealt with replacing the entire window heating system rather than just the battery? The service center quoted 780€ for a complete repair.

Looking at your detailed description, this definitely mirrors what happened with my T-Roc. The simultaneous failure of both window heating systems points to a more complex issue than what I initially faced with my battery problem. The inconsistent resistance readings you measured are very telling. After dealing with similar symptoms, I discovered the main control module for the heating system was faulty. The quoted 780€ repair cost matches what I paid, which included: Control module replacement, Heating coil connection repairs, System recalibration, Complete window demister testing The auto defrost functions started working perfectly after the repair. Based on your multimeter readings and my experience, getting the entire system replaced is the right call. Simply clearing error codes or replacing individual heating elements wont solve the core issue. The fact that your battery tests normal but the window demister still fails supports the control module diagnosis. Just ensure the workshop thoroughly tests the new module after installation, as proper calibration is crucial for the car defrost system to work correctly. Looking back, I should have addressed the heating issue sooner when I first noticed inconsistent performance. The complete repair ultimately proved more reliable than attempting partial fixes.

Appreciate the detailed feedback about the control module. Your repair experience matches what I suspected about my T-Roc defrost system issues. The resistance readings were the key indicator something was wrong beyond just the heating coils. Given the similar symptoms and repair costs, I will proceed with the full system replacement. Good point about ensuring proper calibration, will make sure to request thorough testing of both the front windshield heating and rear window heater after installation. The 780€ quote seems reasonable considering the scope of work needed. Better to fix the entire window demister system properly than risk continued issues with the defroster this winter. Will schedule the repair next week to get it sorted before temperatures drop further. Thanks for confirming my diagnosis. The simultaneous failure of both heating zones and those irregular resistance readings definitely point to the control module being the culprit rather than just faulty heating elements or wiring.