Checking the thermal switch (Mitsubishi Lancer 3)

The thermal switch is mounted at the bottom of the radiator next to the drain nipple. When the coolant reaches a certain temperature, it turns on the electric fan. The switch should be checked if the electric fan does not turn on when the radiator is hot. Test conditions: the thermostat and the drain valve of the radiator cap are working normally. If these parts are defective, the thermal switch does not turn on the fan, since it is not heated by the coolant.

Remove the thermal switch connector.

Short-circuit both connector contacts with a wire. If the fan turns on, replace the thermal switch.

Otherwise, check the contacts and reliability of the fan motor connector connection. Check the wiring, relay and fan motor according to the electrical diagram.

Screw on the new thermal switch with a tightening torque of 30 Nm. First apply a sealant to the threads, for example, MITSUBISHI 3M-ATD-8660.

Fill with coolant.

Warm up the engine and let it idle until the fan comes on. Check the coolant level again.

You can check the thermal switch even when it is removed. To do this, connect an ohmmeter to its contacts.



Place the thermal switch in hot water up to the thread and measure the resistance. At 85° ±3°C the resistance should be 0, at temperatures below 78°C it should be ∞.