The aux fan on that & most newer Benzs are computer controlled! The A/C system relays info to the fuel computer & the fuel computer turn the fan to the desired speed. IF the system THINKS there is too much A/C system pressure OR that the engine is too hot THEN the fan will run all of the time!

MOST of the time a scanner with live data ability can find that problem quickly!

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MERCEDES Benz Master Guild Technician (6 TIMES)
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190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
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