Pope

I have a c240 4matic. I recently had the water pump alternator and fan assembly replaced. But now the fan is running from the time i turn the car on until it turns off. what could it be? also my engine light is on now.

ontmiss

Probably mechanic who changed water pump and fan disconnected temperature sensor and forgot to connect.

Glyn M Ruck

+1 or the temp sensor has failed. It must turn off. The function can be tested with a Star DAS.

Pope

if the sensor has gone bad, is it a simple repair I could do myself?

Thanks for input too guys

Glyn M Ruck

Yes

HeatherDavis

How come when the fan is constantly running, it's automatically assumed the fan needs to be replaced. I had my car put on computer and it coded p2004. When I called the dealer it was like pulling teeth on what it meant, the auto zone store gave the report told me to confir With dealer. I had to basically bager the service guy to tell me what the code meant for my car. He told me the core tempertaure sensor, or coolant temperature sensor.

HeatherDavis

By the way I have a c230 sport

mototech

hi.sorry i am a new member,hope i get it right.
recently had a 203 in the workshop and had the same problem.i found that there was a bad contact at a connector below the radiator fan motor,next to the main plug of the fan.if i remember correctly it is 3 wires connector and it is a signal wire for the air conditioner switch.remove the sump guard it is easy to get to from under -remove the connector and clean inside with electrical contact cleaner/spray.please remember to disconnect the battery first.

Pope

I replaced many things thinking it was all of the above. For me it ended up being my ECM. Cost me 2500 buckaroos. Hope thats not whats wrong with your vehicle.

mototech

hi sorry for the late reply always busy in the workshop
its the same problem as mentioned in the last post - wire is corroded.