When the car's AC system stops working completely, there could be several potential reasons for the issue. Some common causes include:
Electrical issue: The AC system relies on various electrical components, such as fuses, relays, and switches. If any of these components fail or experience a wiring issue, it can lead to a complete AC failure.
Blower motor failure: The blower motor is responsible for pushing air through the vents. If it malfunctions, you won't feel any air coming from the vents, regardless of whether it's hot or cold.
Refrigerant leak: The AC system uses refrigerant to cool the air. If there's a leak in the system, the refrigerant level may drop, causing the AC compressor to shut down to prevent damage. This would result in no cool air coming out of the vents.
Faulty AC compressor: The AC compressor is the heart of the AC system. If it fails, it won't be able to compress the refrigerant, resulting in no cooling effect.
Clogged orifice tube/expansion valve: These components regulate the flow of refrigerant through the system. If they get clogged or stuck, it can prevent the proper circulation of refrigerant, leading to AC failure.
Broken blend door or actuator: The blend door controls the mix of hot and cold air. If it gets stuck or the actuator fails, the system may not be able to adjust the temperature.
Faulty temperature sensor: The AC system relies on various sensors to determine the temperature and adjust the cooling accordingly. A malfunctioning temperature sensor could cause the system to behave erratically or shut down.
Broken belt: In some cars, the AC compressor is driven by a belt connected to the engine. If this belt breaks, the compressor won't function, resulting in no cooling.
To diagnose and fix the issue, it's best to take your BMW F10 to a qualified mechanic or a BMW dealership. They will be able to perform a proper inspection, use diagnostic tools, and identify the exact cause of the AC failure. Electrical issues may require specialized equipment for diagnosis, while refrigerant leaks will need to be detected and repaired before recharging the system. It's essential not to attempt repairs yourself if you are not familiar with automotive AC systems, as incorrect handling could lead to further damage and increased repair costs.