190E 2.3 (201.028) L4-2.3L (102.985) (1987)
Radiator Cooling Fan Temperature Sensor / Switch: Description and Operation
Temperature Switch (100/110 Degree C)
High Temperature Switch Location
PURPOSE
The combination 100°C/110°C temperature switch, which is located near the thermostat housing, has two functions. One switches the electro-magnetic
engine fan clutch "ON" and the other activates the auxiliary fan high speed circuit.
OPERATION
At coolant temperatures of approx. 230°F (110°C), the 110°C temperature switch completes the ground circuit for the high speed fan relay, activating the
auxiliary fan (high speed). As the temperature drops below approx. 217°F (103°C) the circuit is opened and fan operation discontinues.
At coolant temperatures of approx. 212°F (100°C), the 100°C temperature switch completes a ground circuit for the compressor cut-out control unit. The
compressor cut-out control unit then activates the engine electro-magnetic fan clutch. As the temperature drops below approx. 200°F (94°C) the
grounded circuit opens and engine fan operation discontinues.