Cooling Fans and Motors
The cooling fan draws air through the radiator and condenser when the vehicle is stationary or moving too slowly for natural airflow to do the job.
What it does
An electric motor drives the fan, switched by a temperature sensor or controlled by the ECU. Many vehicles run the fan whenever air conditioning is switched on, regardless of engine temperature.
Signs a cooling fan is failing
- Overheating in traffic that clears once the vehicle is moving
- Air conditioning that only cools properly at road speed
- The fan audibly not running when the engine is hot
- A fan that runs constantly from key-on, indicating a failed switch or relay
When to replace them
Not scheduled. Replaced on motor failure, or when a resistor pack, relay or switch fails.
What to confirm before ordering
Have these ready and the counter can usually confirm the part in under a minute.
- Whether the fault is the motor, the resistor pack, the relay or the switch
- Whether the fan is supplied with the shroud as an assembly
- Single or twin fan configuration
- Connector type and number of speeds
Cooling Fans and Motors questions
Why does the car only overheat in traffic?
Because at low speed there is no natural airflow through the radiator and the fan is doing all the work. Overheating that clears once you are moving points squarely at the fan circuit.
Is it the fan motor or the switch?
Bridging the switch or applying power directly to the motor separates the two in a minute. A motor that runs when powered directly means the fault is in the switch, relay or wiring.