Mercedes Viano door locking issue

A faulty door contact signal preventing locking or unlocking is not uncommon The door latch mechanism itself or more specifically its car sensor is often the culprit Have you checked the wiring harness and plug connection to the door latch A defective connection can certainly manifest in these symptoms Confirm the contact signal integrity before assuming a deeper issue

Thank you for your insights When you mention contact signal integrity could you elaborate What exactly should I be looking for when examining the wiring harness and plug connection I'm familiar with basic automotive maintenance but terms like signal integrity sound very technical and complicated to me

By contact signal integrity I mean verifying the electrical signal from the door latch car sensor is correctly reaching the control module Inspect the wiring harness for any visible damage frayed wires corrosion Ensure the plug connection is secure and free of corrosion If you lack the tools or expertise to test the signal itself consider a workshop visit A diagnostic scan will pinpoint the fault

I followed your advice and had the wiring harness and plug connection inspected Turns out you were spot on The connection was indeed defective A quick repair costing 95€ and the doors are now behaving themselves The mechanic confirmed the faulty door contact signal was the root cause Thank you again for your assistance