Radiator Cooling Fan Temperature Sensor / Switch: Description and Operation

These models use one thermo sensor and three relays to control cooling fan operation.
With A/C off and engine coolant temperature below 205°F, the cooling fans will not operate. When coolant temperature exceeds 207°F, relay No. 1 closes and cooling fan operates at low speed. When coolant temperature exceeds 225°F, relays No. 2 and 3 close and cooling fan operates at high speed.
With A/C switch on and engine coolant below 201°F, relay No. 1 closes and cooling fan operates at low speed. When coolant temperature exceeds 03°F, relays No. 2 and 3 close and cooling fan operates at high speed.