What is the "Multi-function sensor" used for W211 model? It's it one of control module in the vehicle?

 

it's an input signal for the AAC control unit as the basis for calculating the climate control, recirculated air control and for the actuation of the refrigerant compressor. it records the ambient temperature, humidity, pollutant concentration of the air drawn in. it is located in the left rear of the engine compartment.

 

Thanks for your reply.. this is normally install outside at engine compactment, will this cause premature failure due to huge of heat facing to this sensor? As my experience, this was causing intemittent failure but it was function back to normal after we dried it by sunlight... how to say?

Another question of me is what is the "tow sensor" used for in W211?

 

Have you ever seen an E Class Mercedes?

 

when checked by star diagnosis the multi-function sensor appeared as a fault? i haven't experienced that one before but what i would do is just to replace it to keep the customer from coming back again. i haven't tried opening the sensor yet if it has a semiconductor device (transistor) that needs heat sink and what is the design of the PCB.