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Marty, ASE Certified Technician
Category: Mercedes
Satisfied Customers: 54832
Experience:  Bosch Certified Master Technician with over 35 years experience in the automotive industry.
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I have a LHD 2007 S320 CDI. The command screen shows my air

Customer Question

I have a LHD 2007 S320 CDI. The command screen shows my air con is off. When I tick box for aircon to start within a few seconds the tick disappears and the aircon stays off. The vehicle was parked unused for 5 weeks. The aircon was fine before. *aircon = climate control.
Malcolm Southey
Submitted: 4 years ago.
Category: Mercedes
Expert:  Marty replied 4 years ago.
Hi Malcolm, my name is Marty. Just to be clear, is it the fan that is not working or are you just getting no cold air from the vents?
Customer: replied 4 years ago.
The fan is working fine. It's the compressor than does not seem to kick in. So it's only non cooled air through vents.
With the command screen there are no warning advisory lights coming on.
Expert:  Marty replied 4 years ago.
Ok, that is what I suspected was happening. This fault is typically caused by low refrigerant charge in the system. When the system pressure is low the control module turns off the compressor to protect it from damage. It's not unusual to see this happen when the car has been sitting. You will need to have the system evacuated and recharged and a leak test should be performed to locate the leak. If it is a slow leak some leak tracing dye can be added to the system for future inspection. It's also possible that the compressor or a sensor has failed but it's unlikely to have happened from just sitting idle. Low refrigerant is the most likely problem. You might also need to have the fault codes in the climate control system read and erased after recharging the system. If low refrigerant is not the cause there will be fault codes stored that will point to the problem.

Let me know if you have any questions.