If a Mercedes LED headlamp sometimes remains on after switching the lights off, save the exact messages and codes. A lighting warning can involve the lamp, its controller, the vehicle wiring or software configuration.
Vehicle-specific technical example
HELLA describes software-related symptoms on selected LED-equipped Mercedes model series 167, 177, 213, 238 and 257 from 2017–2020. Its example includes U118A02, B178392 and U120B97 together with low-beam or high-beam-assistance warnings. The recommended diagnostic route excludes other causes before an appropriate manufacturer software procedure is considered. Read the HELLA technical reference.
Before arranging a module assessment
Do not treat those code numbers as universal descriptions for other makes or configurations. For a replaced headlamp, provide the original and replacement labels and any programming report. A mechanically installed lamp and a correctly commissioned lighting system are separate things to verify.
What to include in your enquiry
Tell us which side is affected, whether the lamp stays on or goes out, and whether the symptom began after accident repair, battery work or a headlamp replacement. Retain the full code suffixes and reporting-module names.
Choose the right next step
AXION Automotive welcomes electronics enquiries from owners and garages in Didcot, Oxford, Reading and across the UK. Discuss the relevant assessment service before travelling or posting a module. Support and repairability depend on the exact vehicle, unit and fault.
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