Mercedes-Benz GLA Body Control Module Replacement Parts

Yes, the GLA has a Body Control Module (BCM), sometimes referred to as a SAM (Signal Acquisition and Actuation Module) in Mercedes-Benz terminology — this unit manages functions including lighting, central locking, and wipers across all GLA variants. It is fitted to every version of the GLA regardless of engine or drivetrain, so whether you have a petrol, diesel, or 4MATIC model, the car will have one. When searching with breakers, be aware that Mercedes-Benz may list it as a SAM unit rather than a BCM.

The first-generation GLA (X156) ran from 2013 to 2019, with a facelift in 2017, so a 2014 car is pre-facelift and a 2018 is post-facelift — both sit within the same generation but on either side of that facelift boundary. Software and wiring updates introduced at the facelift mean a direct swap across that 2017 boundary carries real risk, even though the underlying platform is shared. We'd strongly recommend confirming compatibility with the breaker using both full registration numbers before purchasing.

Yes — the second-generation GLA (H247) launched in 2020 and is a substantially different vehicle from the first-generation X156, with a new electrical architecture. A BCM or SAM unit from an H247 will not be compatible with an X156, and vice versa, so it is essential to know which generation your car is before sourcing. Always give the breaker your full registration so they can confirm the correct unit.

Trim level — whether your GLA is an SE, Sport, AMG Line, or similar — does not fundamentally change the BCM fitment requirement, as the core module is the same across trims within the same build date range. That said, higher trims may have additional options coded into the unit (such as parking sensors or upgraded lighting), so while the physical part may interchange, the module will need coding to your car regardless of where it came from. Always have a used BCM coded to your vehicle by a suitably equipped technician after fitting.

Engine type — petrol or diesel, and whether the car is 4MATIC or front-wheel drive — is generally less critical for BCM fitment than the build date and generation of the donor car, since the BCM handles body electrical functions rather than engine management. However, some variants with additional hardware (such as 4MATIC models with extra control functions) may have subtle differences in module specification, so confirm the engine and drivetrain of the donor car matches yours with the breaker. Coding the replacement unit to your car is essential in any case.

Mercedes-Benz SAM/BCM units are vehicle-specific and, even where hardware looks similar across models sharing a platform, software and configuration differences make cross-model swaps unreliable. The GLA shares underpinnings with other Mercedes-Benz compact models from the same era, but we would not recommend assuming a unit from a different model will work without the breaker confirming it against both registration plates. Any used BCM will require professional coding to your specific vehicle before it will function correctly.