300SDL (126.125) L6-3.0L DSL Turbo (603.961) (1987)
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Radiator Cooling Fan Temperature Sensor / Switch: Description and Operation
Coolant Temperature Switch (S25/11)
PURPOSE
The 105/120°C temperature switch activates the auxiliary fan via the high speed relay, and deactivates the compressor clutch via the compressor cut-out
control unit to prevent engine overheat.
LOCATION
The 105/120°C temperature switch is located near the front of the cylinder head.
OPERATION
At coolant temperatures of approx. 221°F (105°C), the temperature switch activates the auxiliary fan (high speed), via the high speed fan relay. As the
temperature drops below approx. 206°F (97°C) the circuit is opened and fan operation discontinues.
At coolant temperatures of approx. 262°F (128°C), the 120°C temperature switch disengages the A/C compressor via a ground signal to the compressor
cut-out control unit. As the temperature drops below approx. 244°F (118°C) the temperature switch circuit is opened, reactivating the compressor.
