Audi S8 AC System Complete Failure & Repair Tips

Experienced similar AC issues on my 2010 Audi A8 last summer. The complete system shutdown you describe matches what happened, no cold air and no response from controls. The root cause was a failed AC relay combined with a faulty pressure switch. These components work together to protect the system, and when they fail, the entire AC stops working as a safety measure. After diagnosis, repairs involved: Replacing the AC relay unit, Installing new pressure switch, Recharging the refrigerant system, Testing the blower motor function This was a serious repair requiring specialized diagnostic equipment. The AC system in these luxury models uses complex temperature control modules, and complete failure often indicates multiple component issues rather than a single part failure. Important advice: Get this checked quickly as continuing to run the system with failed components can damage the compressor. The pressure switch particularly is a critical safety component, when it fails, it can allow dangerous pressure levels in the AC lines. Based on the symptoms, you likely have a similar relay/switch failure rather than just a refrigerant leak. Have a certified Audi technician perform proper diagnostics with manufacturer-specific testing equipment.

Had almost identical symptoms on my S8 a while back. Total AC system shutdown with no response. The technician found both a bad AC relay and pressure switch, which explained why the cooling system stopped working completely as a safety measure. After fixing those components and doing a refrigerant leak check, everything worked perfectly again. The pressure switch repair was essential since it protects the AC compressor from damage. Do you remember roughly what you paid for the repairs? Also curious if youve had any other AC maintenance issues pop up since getting it fixed?

Following the mechanic visit, my AC system has been working flawlessly. The repairs focused on replacing defective valves in the temperature control system, which was causing the complete shutdown. The total cost came to 1000 Euro, including parts and labor. Since fixing the pressure switch and other faulty components in the cooling system, I havent experienced any additional AC problems. The refrigerant levels have remained stable, suggesting there are no current leaks in the system. Its been a relief having properly functioning climate control again, especially since these luxury vehicles rely heavily on complex AC components. The investment in proper repairs by a qualified technician was worth avoiding potential compressor damage that could have resulted from continuing to run the system with failed components.

The repair turned out exactly as discussed. After taking my S8 to a certified shop last week, they confirmed both the AC relay and pressure switch needed replacement. The blower motor and other cooling system components checked out fine. Total cost ended up at 950 Euro including parts, labor and a complete system recharge. While not cheap, it was worth getting it done right to protect the AC compressor from further damage. The repair shop completed everything in one day and the AC has been working perfectly since then, cold air blowing strong with no unusual noises. Really glad I didn't wait longer as they mentioned the faulty pressure switch could have led to more expensive compressor issues. For anyone facing similar AC problems, getting proper diagnosis early definitely saved me from bigger headaches down the road. Much better than my previous experience where shortcuts led to repeated issues.