Smart Forfour AC System Dead: Blower Works, Cooling Gone

Having some experience with AC systems, I faced a similar issue with my 2018 Smart Forfour. The AC symptoms were identical to what you describe, no response when pressing the AC button while the ventilation worked fine. After a thorough AC maintenance check, the workshop found multiple issues with the pressure switch and cooling system valves. The diagnosis revealed defective individual valves in the air conditioning system, which prevented proper refrigerant flow and system activation. The repair involved: Complete system diagnosis, Replacement of faulty AC valves, Refrigerant leak test, System recharge, Testing AC efficiency Total cost was around 1000€ including parts and labor. The repair took about 6 hours to complete. Before suggesting specific solutions, could you provide: Mileage of your vehicle, Any warning lights on the dashboard, Whether you notice any unusual sounds when trying to activate the AC, When was the last AC service performed, If you noticed gradual performance decline or sudden failure This information would help determine if you are dealing with the same valve issues or potentially different AC system problems.

Thanks for the detailed response about the AC valve issues. My Forfour has 62183KM on the odometer and no warning lights are present. During AC diagnostics last week, I noticed a faint clicking sound when pressing the button, but no other AC noise. Temperature control remains unresponsive. The last full service including AC check was done 6 months ago with no issues reported. The failure was quite sudden, worked fine one day, completely dead the next. Your repair cost information is helpful for budgeting if I end up needing similar valve replacements. Will get it checked for refrigerant leaks and pressure switch issues as those seem like common failure points based on your experience.

Thanks for providing those additional details. When comparing with my Forfour repair case, the sudden failure and clicking sound actually match exactly what I experienced before the valve issue was diagnosed. The clicking likely comes from the pressure switch attempting to engage but failing due to system pressure problems. Based on your 62183KM mileage and the symptoms, this really does sound like the same valve and pressure switch combination failure I dealt with. The cooling system in these models seems prone to developing these issues around the 60000KM mark. One thing I noticed after my repair was that the clicking noise completely disappeared once the new valves were installed and the refrigerant levels were correctly set. The blower motor continued working normally throughout, which matches your situation. Since your last service was relatively recent, I would specifically ask the workshop to inspect the pressure switch and cooling system valves first, rather than starting with a complete system diagnosis. This could save you some diagnostic time and costs compared to my repair bill of 1000€. Given the matching symptoms and similar vehicle age, I strongly suspect youll need the same valve replacement work I had done. The good news is that once fixed, my AC has worked flawlessly for the past 18 months.

The clicking noise you mention matches what I was experiencing, so this is really helpful information. The 60000KM timeframe for valve issues also makes sense given my mileage. Will definitely have the shop focus on checking the AC relay, pressure switch and cooling system valves first. Getting those components inspected before a full system diagnosis should help control costs. The clicking when pressing the AC button does suggest the pressure switch might be the culprit, especially since the temperature control and blower motor ventilation are working normally otherwise. Really appreciate you sharing the repair details and costs. 1000€ for the fix is significant but at least I know what to budget for if it turns out to be the same valve replacement work. Good to hear your AC has remained reliable after the repair. Will schedule a workshop visit next week focusing on these specific components rather than starting with a full diagnostic sweep. Thanks again for helping narrow down the likely cause. Having a reference point from someone who dealt with identical symptoms definitely helps reduce some of the uncertainty around the repair process.