Mercedes: mercedec c280 cooling fan not working, ac condenser, mercedes c280

Question
QUESTION: hi  my mercedes c280  4matic 2006 model the radiator fan is not working even if the engine over heating ,but if i but the air condation on the fan will work but if i off the air condation will go off ,many cares rewyers work on it but no result what is the problem pleas help even electrecian test the fan and the auxelary and said is working



ANSWER: armain,
The cooling fan is controlled through a temperature sensor in the engine block probably near the water inlet. When the sensor goes bad, it will not call for the fan to run. It you have a single fan then the fan is hard wired through the AC control to make sure the fan operates full time to help remove the additional heat that is created by the AC condenser.
If you have two fans, then one is operated by the radiator thermostat sensor and the other is hardwired into the AC control.
I would look at the block heat switch and replace that first.
Good Luck Let me know what you discover.
Robert

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QUESTION: thanks ,i have to remove out the compleet thermostat housing becouse the temp sansor attatched permenantly to the housing and when i test the 2 head for the sansor was reading tell end of the meeter it loke like the sansor bridg insite ,do you think the sansor is faulty and not make the fan pick up, becouse is bridg insite ,or as its bridg this sapouse to make the fan working all time but my fan is not working,what do you think?   thanks friend
armain

ANSWER: and when i test the 2 head for the sansor was reading tell end of the meeter it loke like the sansor bridg insite

I do not understand this sentence.??

If the sensor has two wires, it should normally be in the open position. As the temperature rises, the sensor should close and connect the fan wire to the Negative ground. This will allow electricity to flow from the battery through the fan motor and to the ground.
The fan would continue to operate, until the fluid temperature cools and allows the switch to open and disconnect the power to the fan.
Let me know if you have questions.
Rob

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QUESTION: sorry ,i mean when i test the sansor where is the wirs was connacted , the meeter contenuty reading tell end as the 2 lines are connacted togather and when i test eatch line and the body is reading to end  

Answer
Armain,
Usually, the sensor should be open when cold.. no continuity.... as the the temperature rises, the sensor closes and allows power to the fan.
Robert

Try thisArmain... Take a wire and connect the wires coming to the sensor together. Turn off the AC and turn on th e ignition switch to run position.  The fans should operate because you have used the wire to close the circuit.
This will indicate that the sensor in now working properly.
Robert