Radiator fan thermal switch - testing, removal and refitting

Testing
1 The thermal switch is located on the side of the thermostat housing on early OHV engine models and in the thermostat housing cover on later OHV versions. On all CVH engines, the switch is located in the thermostat housing. If the operation of the radiator fan is suspect, the thermal switch may be tested as follows.

2 Disconnect the wiring plug and bridge the two plug terminals with a length of wire or suitable metal object. The fan should now operate with the ignition switched on. If it does, the thermal switch is proved faulty and must be renewed. If the fan still does not operate, check the appropriate fuses, wiring and connections. If these are satisfactory it is likely that the fan motor itself is faulty.

Removal
Note: A new sealing washer will be required on refitting.

3 To renew the thermal switch wait until the engine is cold, then remove the pressure cap on the thermostat housing or expansion tank as applicable.

4 Place a container beneath the thermostat housing to collect the small amount of coolant that will be released when the switch is removed.

5 Disconnect the wiring plug and unscrew the switch from its location.

Refitting
6 Using a new sealing washer, refit and tighten the switch securely. Fit the wiring plug and top-up the system as described in Chapter 1.

    See also:

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