Mercedes A Klasse sensor issue

The symptoms you describe certainly point towards a malfunctioning fog or humidity sensor Given the interconnected nature of modern automotive sensor systems, a failure in one area can cascade into seemingly unrelated issues The A/C, spray nozzles, and mirror heating relying on input from this sensor for optimal operation isn't unusual Have you checked the wiring harness and connector leading to the sensor itself for any signs of corrosion, damage, or loose connections? A visual inspection is the first step Prior experience suggests that even a slightly dislodged connector can cause such widespread problems Accessing the component may require removing some trim or panels, so proceed cautiously to avoid further damage Consider also if any recent work was done near the sensor, as it may have been disturbed

Thanks for the quick reply I visually inspected the wiring harness as best I could, but it's pretty tight in there I didn't see anything obvious You mentioned 'accessing the component' Is there a specific procedure or diagram you'd recommend for locating the fog sensor on this model? I want to be sure I'm checking the right automotive sensor and not messing with something else entirely

Confirming your suspicions, the fog sensor is indeed the likely culprit While a detailed procedure is beyond the scope of this forum, your best course of action, given the potential complexity and interconnectedness of the system, is to visit a qualified Mercedes-Benz workshop They possess the necessary diagnostic equipment and expertise to pinpoint the exact cause of the fault, be it the sensor itself, the wiring, or a related control module While a visual inspection is a good starting point, specialized tools are often required to properly diagnose such issues

Understood I appreciate the confirmation I'll book it into a workshop and have them run a proper diagnostic Turns out, after taking it to the workshop, it was exactly what we thought: a defective cable connection on the sensor They cleaned and secured it, and everything is working again Thanks for pointing me in the right direction