BMW 740iL Air Conditioning Condenser Fan Assembly Replacement Cost

The air conditioning system works by changing the phase of refrigerant by altering pressure and heat at different stages as it passes through the refrigerant system. One of those stages is passing high pressure and high heat refrigerant through the condenser where it can be cooled by airflow. Since the vehicle needs to be moving at a high rate of speed for maximum airflow, a condenser cooling fan is used to pull air across the condenser, therefore providing a high rate of airflow even when the vehicle is stopped.

The air conditioner cooling fan is electrically powered on modern vehicles, and older vehicles typically use a clutch-driven fan for the radiator and air conditioning condensor. Vehicles with a dedicated air conditioning condenser fan will have two fans, a radiator cooling fan, and an air conditioning condensor cooling fan. The condenser fan is typically a smaller fan which is mounted on the radiator to pull air from the front of the vehicle through the radiator and condenser. This allows added cooling for the radiator, and rapid cooling for the condenser.

Like all air conditioning refrigerant system issues, an improperly functioning or failed cooling fan will lead to decreased performance of the air conditioning system for the vehicle. When the fan stops working, the pressure and heat inside the refrigerant system will become too high and hot, so the control module will likely turn off the a/c compressor and signal the a/c button in the cabin to begin blinking. The air conditioner may blow cold air intermittently, but will always return to blowing hot air.

Most vehicles only use the air conditioning fan as an auxiliary fan for the radiator when the radiator cooling fan is not capable of reducing the engine coolant temperature to specified levels. Since this may be necessary, a failed air conditioning condensor fan could allow the vehicle to overheat under heavy load. Aside from this risk, there is no immediate need to repair the condenser cooling fan except to return the vehicle cabin to a comfortable temperature.

Condenser fans on average last over 100,000 miles, with the bulk of replacements occurring at the 110,000 - 125,000 mile interval. There is no clear means of preventing the condenser fan from failing, but there is also a risk of road debris causing damage to the fan during normal operation. Ensuring the plastic guards underneath the vehicle are intact and secured in place can help prevent road hazards to the condenser cooling fan.

If the condenser fan is cracked or broken the technician will hear noise and feel vibration, and a quick inspection will yield that the fan is the cause. However, a condenser cooling fan which is not functioning has several possible causes. The technician will first check for power at the fan when the air conditioner is turned on. If the fan has power but will not function, the fan will be removed and bench tested to make the determination of the condition of the fan motor. If there is no power, the technician must locate the cause for loss of power, which may be a bad relay, faulty wiring, or even the air conditioner control module.

Replacing the cooling fan for the air conditioning condenser will likely require the radiator and condenser fan assembly to be removed as a unit, and the condenser fan can be separated once the unit is removed. Once the new condensor fan is replaced, the assembly can be reinserted into the front of the engine bay, secured to the radiator core support, and connected electronically before testing.

We do not recommend the air conditioning system be used in the event the condenser cooling fan has failed or is failing. This can result in abnormal pressures in the refrigerant system, undue wear on the air conditioning compressor, and leaking seals.

Many models of vehicles will have multiple sizes of condenser cooling fans, and the size of the cooling fan is typically not listed on the part for reordering the fan. Instead, the part number should be used when ordering the new condenser fan to ensure receipt of the proper components.

This can be a good job for the DIY mechanic to tackle in an evening or weekend. Testing the fan and fan circuit should be done with the assistance of the service manual and wiring schematic to ensure an accurate diagnosis. As long as safety precautions are taken against electric shock, this job should go smoothly.