Condenser Fan Motor: Essential Guide for Efficiency

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Purpose

The Condenser Fan Motor powers the air conditioning condenser fan. This fan draws air trough the condenser to cool refrigerant circulating through the air conditioning system.

Location

If the vehicle is so equipped, the condenser fan motor is located behind the cooling system radiator, mounted to the center of the assembly that houses the condenser fan. 

The air conditioning condenser, which looks like a smaller version of the cooling system radiator and is essentially the radiator for the air conditioning system, is located in front of the cooling system radiator, positioned so that the condenser covers only a portion of the radiator.

Many vehicles equipped with air conditioning are not equipped with a condenser fan. These vehicles employ the cooling fan or fans to draw air through both the radiator and the air conditioning condenser.

Operation

Air conditioning functions by initially compressing the refrigerant, which heats it. The heated refrigerant is then circulated through the condenser to cool it. The cooling also expands the refrigerant, further decreasing refrigerant temperature. 

The refrigerant then circulates through the evaporator, which is a series of finned passages through which air passes to cool the vehicle interior.

The condenser fan is electrically powered. It initially operates whenever the air conditioning compressor is engaged. After that, it is controlled by the engine or powertrain control module (ECM/PCM) based on monitored airflow temperatures through the interior vents.

Drivability Symptoms

If the condenser fan is not operating, air flow through the condenser when the vehicle is stopped or moving at low speed will not be adequate to cool the refrigerant. 

As a result, air exiting from the air conditioning vents will not be properly cooled and may actually be warm. The air becomes cooler at higher speeds, as increased airflow through the condenser decreases refrigerant temperature.

Inspection, Test, and Diagnosis

Vehicles and light trucks manufactured for model year 1996 and later use Second Generation On-Board Diagnostics (OBD2) focused on detecting malfunctions affecting vehicle emissions. Because condenser fan motor failure does not affect emissions, there is no generic Diagnostic Trouble Code (DTC) for its failure (generic DTCs are shared by all manufacturers). 

Air conditioning enhanced DTCs (DTCs that are specific to a vehicle manufacturer) generally indicate failures in temperature sensors monitoring airflow through the interior vents. 

Consequently, if any relevant trouble codes are retrieved when diagnosing poor air conditioning performance, they should be investigated independently of verifying condenser fan motor operation.

The condenser fan should operate whenever the compressor is engaged. To verify that the compressor is engaged, place a hand on it to feel for slight vibrations. If the compressor is not operating, the compressor switch may be the cause of both the inoperative compressor and condenser fan motor.

If the compressor operates, but the condenser fan does not, verify that the fan motor is receiving power. BE SURE to stay clear of the compressor and cooling fans during this procedure. The cooling fans may operate even when the engine is not running. 

Remove the electrical pigtail connector from the condenser fan motor. Start the engine and turn on the air conditioning to engage the compressor. Connect a 12-volt test light to a good ground and probe the positive terminal in the connector. If the test light illuminates, power is reaching the condenser fan motor. 

Turn off the engine. Connect a jumper wire from the fan motor’s positive terminal to the battery positive terminal and a second jumper wire from the fan motor’s negative terminal to a good ground. Turn the ignition key on, but DO NOT start the engine. The fan motor should run. If it does not, it is defective.

If the condenser fan motor is receiving power and runs when connected directly to battery voltage, but not when connected to the wiring harness, the fault is in the harness connector or in the fan motor ground circuit. 

If power is not reaching the compressor fan motor with the air conditioning compressor engaged, the fault is a defective condenser fan motor relay or a short or open in the wiring of the relay’s control or power circuits.

Reprogramming

Replacement of a condenser fan motor does not require reprogramming.

Repair/Replacement

In some vehicles, the condenser fan can be replaced only by replacing the entire fan assembly. In others, the fan can be separately replaced. In either instance, the fan assembly must be removed from the vehicle. 

To do that, first disconnect the negative battery terminal and remove the fascia or “sight shield” covering the top of the radiator. These are usually held in place with “push pins,” retainers released by pulling or pushing a pin in within the retainer. 

Disconnect the wiring harness from the fan and remove the bolts holding the fan assembly to the radiator or its support. After moving or removing other components as necessary to clear a path, the fan assembly can be removed from the vehicle. 

If the motor is removable, first remove the fan from the motor, usually by removing a bolt that is reverse threaded (unscrews clockwise). This exposes the bolts holding the fan motor to the assembly. Remove those bolts to remove the fan motor. Installation is the reverse of removal.

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