VW Tiguan AC Failure, Expert Repair Tips & Solutions

Had the same issue on my 2011 VW Touareg TDI. The A/C compressor failed to engage due to an undervoltage condition in the HVAC system. After thorough diagnosis, the problem traced back to two components: The pressure sensor was sending incorrect readings to the control unit, making the system think the refrigerant pressure was too low. The pressure switch also had corroded terminals, which caused intermittent electrical connection. The fix required: Replacing the pressure sensor, Installing a new pressure switch, Recharging the A/C system, Clearing the stored error codes This was a serious repair that required specialized diagnostic equipment to properly identify the voltage issues. The undervoltage problem could have eventually damaged other electrical components if left unaddressed. A certified VW specialist should handle this type of repair since it involves both the A/C compressor circuit and the electronic control systems. They will need to verify proper voltage levels across the entire HVAC system after the repair. The symptoms you describe match exactly what I experienced, no compressor engagement, warning lights, and complete loss of cooling.

Thanks for sharing your experience with the pressure sensor and voltage issues. I had nearly identical symptoms with my Tiguan a few months ago. The AC relay was also failing intermittently along with the faulty pressure sensor. My air conditioning would sometimes work for a few minutes before cutting out completely. Did you remember roughly how much you paid for the full repair? Also curious if you have experienced any other air conditioning problems since getting it fixed. The belt tensioner on my car started making noise shortly after, but that might have been unrelated.

Just got the final bill last week, the complete repair including parts and labor came to 240€. The AC relay switch replacement and fixing the undervoltage issue resolved the compressor shut-off problem completely. After getting the pressure sensor and electrical components sorted out, my A/C system has been working flawlessly. The compressor engages right away and maintains consistent cooling. No more warning lights or error codes either. Your belt tensioner noise is likely unrelated since the pressure switch and electrical repairs dont affect the belt system. The A/C compressor belt tension is a separate maintenance item that should be checked during regular service. For peace of mind, have a mechanic verify the belt tensioner condition, but the intermittent AC issues we experienced were definitely caused by the electrical problems and faulty pressure sensor readings.

That A/C system repair turned out better than expected. Found a highly-rated VW specialist who actually took the time to properly diagnose the electrical issues. The whole job including parts and labor cost me 275€, which seemed fair given all the components they had to replace. The pressure sensor and AC relay were definitely the culprits causing my compressor to act up. Once those were replaced and the system was recharged, the cold air started flowing perfectly again. The warning lights cleared up right away too. Funny enough, that belt tensioner noise I mentioned did end up being a separate issue. Had it checked during my next oil change and it just needed adjustment, no replacement required. Really glad I got a second opinion and didn't go back to my old mechanic who probably would have missed the actual HVAC system problems. The A/C compressor engages instantly now and keeps the cabin nice and cool. No more intermittent shutdowns or error codes. Sometimes paying a bit more for proper diagnosis saves money in the long run.