Date registered: Sep 2006
Vehicle: 2004 CLK 240 Coupe
Location: Norfolk. UK
Mentioned: 9 Post(s)
Quoted: 343 Post(s)
Not sure if this is going to help, as my info is merely from searching the WIS for your model....
I noted that together with the AAM (N10) located in the engine bay, the auxillary fans (M4) are also controlled via the Extended Activity Module (N10/1).
Possibly your fault could lie outside the modules in one of the sensors? The auxillary fans are actuated according to both the refrigerant pressure (B12) and the coolant temperature - as follows:
pressure > 16 bar = ON
pressure < 12 bar - OFF
temperature > 105 degC = ON
temperature < 94 degC = OFF
I also read that these values of temp & press are compared in the AAM with stored values, and actuate the left & right fans accordingly. Maybe this stored value needs re-setting?
Finally, is the cover on your AAM perfectly weatherproof. No sign of rainwater invading the enclosure, is there?