VW Caddy Auxiliary Heater Failure Troubleshooting Guide

I experienced a similar auxiliary heater failure on my VW Golf 2012 TSI. The symptoms matched exactly, complete heater failure with an error code. The diagnostic revealed multiple issues in the climate control system. The main problem was traced to a faulty temperature sensor and a partially blocked heater core. The coolant leak around the auxiliary heating unit had caused corrosion on the electrical connections. This explained why the system stopped responding completely. The repair required: Replacing the temperature sensor unit, Flushing the heater core, Fixing the coolant leak, Cleaning electrical connections, Reprogramming the climate control module This was a serious repair job taking about 6 hours of labor. These issues are common in VW models from that generation, especially when regular maintenance intervals are missed. The auxiliary heater problems often start small but can lead to complete system failure if not addressed early. A proper diagnosis with a VW-specific scanner would be the first step to determine if your issue matches these symptoms. The car heater system in Caddy models shares many components with other VW vehicles from that period, so the repair process should be similar.

Thanks for sharing those details about the heater system repair. Did similar problems come up again since you had it fixed? My auxiliary heater also needed a complete overhaul last winter when the heat control unit failed. The coolant leak turned out to be worse than expected, with significant corrosion around the heater core. Just wondering what the total repair cost was in your case? I ended up paying 850€ for my repair, wondering if that was reasonable or if I overpaid.

After having the auxiliary heater system repaired last month, everything has been working perfectly. The mechanic found that the main issue was actually a defective glow plug, which was causing the system failure. The diagnostic scan helped identify this specific problem quickly, avoiding unnecessary repairs to the heater core or blower motor. The total repair cost came to 440€, which included the parts and labor. This seems reasonable compared to your 850€ repair, but your case involved more extensive work with the coolant leak and corrosion issues in the ventilation system. Each repair varies depending on the specific components that need replacement. The temperature sensor readings now show normal values, and the auxiliary heater activates promptly every time. No coolant leaks or error codes have appeared since the fix. Regular maintenance should help prevent similar issues from developing in the future.

After dealing with the initial heater core problems, I finally took my Caddy to a different repair shop. The mechanic there immediately identified the issue using their diagnostic equipment. Just like they suspected, the auxiliary heater had failed due to a faulty control module and damaged wiring in the heating system. The repair took about 4 hours. They replaced the control unit, fixed some corroded wiring, and did a complete flush of the climate control system. The final bill came to 440€, which actually seemed fair considering the amount of work involved. The ventilation system has been working flawlessly since then. No more error codes, and the heat control responds instantly. Looking back, I should have gotten a proper diagnosis sooner instead of letting the problem get worse. But at least now I know what to watch for and have found a reliable shop that knows their way around VW heating systems.