Used Mercedes-Benz GLS Window Motor

Yes, generation matters significantly for window motor fitment. The GLS has been sold in two generations: the first-generation X166 (2016–2019) and the second-generation X167 (2020 onwards). Motors from the X166 and X167 are not directly interchangeable due to differences in door architecture, so always confirm the generation matches before buying. Check the generation of any part you're quoted against your registration with the breaker.

Yes, side is critical – a window motor is specific to the door it was fitted to. In UK terms, you need to specify NS (nearside, passenger/left) or OS (offside, driver/right) when requesting a quote. A motor from the wrong side will not be compatible, as the regulator mechanism and motor orientation differ between left and right doors. Always tell the breaker exactly which door you need.

Yes, front and rear door window motors are different parts and are not interchangeable. The GLS is a five-door SUV, and the front and rear doors have different dimensions and regulator assemblies, meaning the motors are door-position specific. When contacting a breaker, specify whether you need a front or rear motor as well as the side (NS or OS). Fitting the wrong door position motor will not work correctly.

Engine choice does not affect window motor fitment – all GLS variants across petrol, diesel, and AMG drivetrains use the same door-mounted motors for a given generation and door position. The GLS is offered across various trim levels but trim level alone does not change the window motor specification. You may find minor cosmetic differences around the door trim depending on specification, but the motor itself is determined by generation, door position, and side. Confirm the generation and door details with the breaker rather than worrying about engine or trim.

This is an important boundary to flag: the GLS changed from the first-generation X166 to the second-generation X167 in 2020, meaning a 2019 and a 2020 GLS are different generations with redesigned doors and different components. It is very unlikely a 2020 motor will fit a 2019 car, but whether any specific part crosses that boundary is something you should confirm directly with the breaker using both vehicles' registrations. Do not assume cross-generation compatibility without that check.

The GLS, GLE, and the older M-Class are related platforms but are distinct vehicles with their own door designs, so window motor compatibility across these models is not guaranteed. Some internal components have historically been shared within the Mercedes-Benz SUV family, but door panel dimensions and regulator assemblies can differ. You should not assume a motor from a GLE or M-Class will fit your GLS without checking against both registrations with the breaker. A good breaker will be able to cross-reference part numbers to confirm before you commit.