Fan switch sensor: replacement and selection

When and why a fan switch sensor needs replacement

The fan switch sensor has no specified lifetime limit. Most often replacement is performed after contacts oxidation.

Ingress of water in the engine compartment can be the cause of sensor defects. Influence of moisture affects contacts condition negatively.

Part defects can be indicated by unprompted activation of the fan when the ignition is turned on. Moreover, the fan stops switching on if the sensor is broken. Due to this temperature of the cooling liquid increases leading to engine overheating. Readings of a corresponding dashboard indicator show this.

It is recommended to visit a service station for part replacement. Cooling liquid should be drained before demounting of the radiator fan switch. In order to do this safely, you need a special coolant exchanger machine. Also, wires which supply electric current to the part need be to disconnected before servicing. A seal, which is often sold in a kit should be installed together with the sensor.

How to select a fan switch sensor

According to operation principle sensors are divided into three main types.