Jaguar XJ AC System Dead, Quick Diagnostic Tips & Costs

Having dealt with a similar AC maintenance issue on my 2005 Jaguar S Type last summer, the symptoms you describe point to a potentially serious problem with the AC system. When the system refuses to engage completely, its often linked to either a failed compressor or defective control valves. The AC noise was non-existent in my case because the system had a complete refrigerant leak, which triggered a safety shutdown to protect the compressor. The temperature control module also showed no response when pressing buttons, similar to your situation. A basic AC diagnostic scan revealed multiple issues in my case: the system had lost all refrigerant through a leaking expansion valve, and the pressure sensors had disabled the entire system as a protective measure. The blower motor was fine, but the compressor had suffered some damage from running with insufficient lubrication. In your Jaguar XJ, these symptoms definitely warrant professional attention. Simple diagnostics will quickly determine if its a minor electrical issue or something more serious with the mechanical components. Given the age of your vehicle, its worth having a complete AC system inspection to prevent additional damage to other components. The potential scope of repairs can range from simple refrigerant recharge to complete system overhaul, but proper diagnosis is essential before proceeding with any repairs.

Thanks for sharing your S Type experience. Did fixing all those AC issues require replacing the compressor and expansion valve in the end? The situation with my XJ seems quite similar, especially the part about the pressure switch cutting off the system due to low refrigerant. AC diagnostics would definitely help pinpoint if its just a refrigerant leak or something more serious with the blower motor or electrical components. Would you mind sharing what was the total repair cost in your case? And has the AC system been running problem-free since the fix?

Our AC efficiency issues were indeed similar, and I can confirm the repair resolved everything completely. The cooling system works perfectly now after the shop found and fixed defective valves in the AC system. The mechanics discovered during diagnostics that the AC relay and pressure switch were still functional, but individual valves had failed. Unlike your XJ, my compressor was actually still in good shape and didnt need replacement despite the initial concerns. The total repair came to 1000€, which covered replacing the faulty valves and a complete AC maintenance service including a new refrigerant charge. Since the fix six months ago, the air conditioning has worked flawlessly with perfect cooling performance. The diagnostic test was definitely worth it as it prevented unnecessary compressor replacement and helped identify the exact failing components. Would strongly recommend getting your XJ checked, it might not need as extensive repairs as initially feared.

Thanks for the detailed response. I took my XJ to the shop last week and wanted to share how it turned out. The AC diagnostics revealed a major refrigerant leak from a cracked line near the condenser. The cooling system had completely lost pressure, triggering the safety shutdown. Thankfully the AC relay and compressor were still in good condition. The mechanic replaced the damaged line and performed a complete system service including new refrigerant and filter drier. Total cost came to 450€, which was much less than I feared given previous Jaguar repair bills. The AC efficiency is now back to factory levels. No strange AC noise or other issues since the repair. Really glad I got it checked instead of waiting, could have damaged the compressor if run too long without proper refrigerant levels. The diagnostic test definitely saved money by pinpointing the exact problem.