One dark lighting strip with the rest working is a different diagnostic pattern from all cabin lighting failing. Record whether the section is always dark, flickers or displays the wrong colour, and whether normal cabin lamps still operate.
Check the user controls first
Use the ordinary brightness and theme settings described in the manual. Compare the affected section across supported colours without assuming that every illuminated trim piece uses the same control arrangement. Include recent trim removal, door repairs or accessory installation.
Do not remove trim around airbags or feed power into an unknown lighting connector. A workshop should identify the local light source, connections and controller arrangement before proposing a body-module repair. Send photographs showing the working and affected sections together. If the problem began after a replacement trim part was fitted, provide its part number and whether it was original, used or aftermarket; physical fit does not establish electronic compatibility.
Related help
Browse all fault guides or use the vehicle module finder to prepare your enquiry. Include the vehicle, symptoms, complete fault codes and any previous test results. Assessment scope and compatibility must be confirmed before booking or sending a unit.