VW Transporter AC Issues: Failed Flap Actuator Fix

I had a similar issue with my 2014 VW Caravelle, which shares many components with the Transporter. Based on some experience working with HVAC systems, this sounds very familiar. The symptoms you describe match what I encountered, the climate control malfunction and error codes were caused by a faulty connection to the flap actuator. After running system diagnostics, my workshop found that the cable connection to the rear flap actuator had deteriorated, affecting air circulation for rear passengers. The repair involved replacing the wiring harness and checking all HVAC connections. Total cost was 95€ and took about 2 hours to complete. The fix resolved both the cooling issues and error codes completely. Before suggesting specific solutions, could you share: Which error code is showing up? Are you getting any airflow at all to the rear? Does the problem occur immediately when starting the vehicle or after some time? Have you noticed any unusual sounds from the climate control system? This information would help determine if your issue is identical to what I experienced.

Thanks for sharing those details. Currently at 140942km on my Transporter and had the last service done 2 months ago. The error code showing is P0645. There is minimal airflow to the rear, and the automatic climate control starts acting up about 10 minutes after starting the vehicle. The air distribution becomes erratic, and there is a faint clicking noise from behind the dashboard when adjusting temperature settings. The air conditioning seems to work briefly but then stops cooling effectively. Would checking the wiring harness be a good first step, or should I have the entire HVAC system diagnosed first?

Thanks for providing those additional details. Looking at your description and comparing it to my Caravelle experience, there are both similarities and differences. The P0645 code and clicking noise actually point to a different issue than what I initially encountered, it typically indicates a problem with the AC clutch relay circuit rather than just the rear flap actuator I mentioned before. The relay issue explains why your air conditioning works briefly then fails. In my case, fixing just the rear flap wiring harness was sufficient, but your symptoms suggest you might need both the relay and a wiring check since the automatic climate control is behaving erratically. When my HVAC repair was done, the workshop first performed a full system diagnosis which caught both the wiring and air circulation issues. Given your symptoms, I would recommend getting the complete diagnostic before replacing any parts. This identified the exact problem areas and saved money on unnecessary replacements. The rear passengers in my vehicle experienced similar airflow issues before the repair. The clicking noise you describe is a telltale sign that the climate control unit is trying to engage components that are not responding correctly. Based on current parts prices, you might be looking at around 180€ for the repair if it requires both the relay and wiring work. The diagnostic fee should be factored in as well.

Thank you for this detailed explanation. I now have a better understanding of what might be needed for my Transporter. The symptoms you described with your Caravelle sound quite similar, though the P0645 code does make my case a bit different. I will schedule a full HVAC system diagnosis first rather than jumping straight to replacing parts. The clicking noise and air distribution issues combined with the AC clutch relay circuit problems definitely warrant a complete check. The 180€ estimate for parts and labor seems reasonable compared to what I was worried it might cost. The automatic climate control issues and poor air conditioning performance have been quite frustrating, especially with the erratic air flow to the rear. Knowing that these problems can be diagnosed and fixed properly is reassuring. I will get this looked at this week before the system potentially develops more serious issues. Just to confirm, did your repair also resolve any intermittent cooling problems, or was your case strictly related to the air circulation? This might help me better understand what to expect during my repair.