I washed my 190 e 2.3 with engine degreaser shortly afer that the condenser fan start acting up. It runs all the time whether hot or cold.
I tested the two sensors that sits ontop of the water pump, infact i blew compressed air into and around them. and still the fan on my 190 e 2.3 still wont shut off. I even unplugged the blue connector near the air cleaner. So whats next?

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What year car? If you are talking about the BLUE switch(2 pin connector) on the front of head, then that is probably the problem. On 1988 & later cars that sensor is a varible resistor & must send the correct info to the A/C pushbutton or the fan will run! Unplugging or jumping this switch makes the fan run!

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MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. TECH
190E 2.3 ITS RACECAR