The radiator cooling fan on the Ford Escort is controlled by a thermostatic switch located within the thermostat housing. As the coolant heats from dissipating the heat from the engine, the cooling fan switch will close, allowing the cooling fan to run. The fan draws air through the radiator, which exchanges the heat in the coolant with the passing air. If the cooling fan switch fails, the fan will either not run at all, or run continuously regardless of the coolant temperature. If the coolant switch is determined to be defective, it should be replaced with a new one.
Open the petcock (drain plug) located at the bottom of the radiator. Drain enough coolant out of the system to access the cooling switch located within the thermostat housing.
Close the petcock valve after draining coolant from the radiator.
Locate the cooling switch connected to the thermostat housing at the top of the radiator. Once located, remove the two-wire plug from the switch.
Unscrew the threaded cooling switch from the thermostat housing and set it aside.
Install a new cooling switch gasket onto the new coolant switch in preparation for installation.
Screw the coolant switch into the thermostat housing and tighten.
Re-connect the two-wire plug into the coolant switch by plugging the switch in until it seats completely.
Re-fill the expansion tank connected to the radiator with the proper ratio of engine coolant.
Start the vehicle and inspect for proper radiator fan operation. If the fan works as expected, the coolant fan switch is functioning properly.
