Second Hand Mercedes-Benz GLS Engine Wiring Loom

The GLS spans two distinct generations: the X166 (2016–2019) and the X167 (2019 onwards), so a 2017 loom comes from the X166 and a 2020 loom is X167 — these are completely different platforms and the looms are not interchangeable. Even within a generation, fitment depends heavily on your exact engine code, which you'll find on your V5 or via a VIN check. Always confirm the engine code with the breaker before purchasing.

No — petrol and diesel looms are engineered specifically for their respective engines and management systems, so fuel type is a critical factor. The engine code (for example, OM656 for certain diesel variants or M176 for petrol) tells the breaker exactly which loom is correct, far more reliably than fuel type alone. Always supply your full engine code when requesting a quote.

The 400d and 580 are entirely different engines (diesel versus petrol V8) with completely different wiring looms, so in this case the badge does reflect a genuine mechanical difference. Where two vehicles share the same engine code, trim level makes no difference to loom fitment — it is the engine code that matters, not the trim name. Confirm your engine code with the breaker to ensure an exact match.

The X166 generation ran from 2016 to 2019, and Mercedes introduced the all-new X167 platform in 2019 rather than a mid-cycle facelift of the X166, so the generational boundary here is a full redesign rather than a facelift. Within the X166 production run there may have been ancillary or connector changes that affect loom compatibility, so you should confirm the exact engine code and build date with the breaker against your registration before buying.

Engine wiring looms on modern Mercedes-Benz vehicles can be associated with the vehicle's ECU and immobiliser systems, which may require coding or adaptation after fitting. Whether a specific used loom will need reprogramming is something you should confirm with your fitting garage and with the breaker, as this is not straightforward to advise on without knowing the exact units involved. This is worth clarifying before you buy to avoid unexpected costs.

The single most useful piece of information you can supply is your engine code, which is printed on your V5 logbook or can be obtained from a VIN check — it will be something like OM656, M176, or M177 depending on your variant. Also provide your build year and confirm the generation (X166 2016–2019 or X167 2019 onwards) so the breaker can cross-reference their stock accurately. Never rely on the model name or year alone, as multiple engine variants were sold under the same GLS badge.