Cheap Mercedes-Benz GLS Ignition Switch

The Mercedes-Benz GLS (X166, produced from 2016, and X167, produced from 2019 onwards) was fitted with a keyless push-button start system as standard across all variants sold in the UK — there is no traditional barrel-style ignition switch on this model. The component you are most likely looking for is the start/stop button, the steering column electronic ignition module (EIS/EZS), or the keyless go control unit, depending on the fault you are experiencing. Confirm with a breaker exactly which component matches your symptom and registration before ordering.

On the GLS, the functions normally associated with an ignition switch are handled by the Electronic Ignition Switch (EIS) module, which sits in the steering column and communicates with the key fob electronically. If your GLS will not start, is showing key or immobiliser faults, or the start button is unresponsive, the EIS module or the start/stop button assembly are the parts most likely to be at fault. Search for 'Mercedes GLS EIS module' or 'GLS steering column ignition module' and quote your registration to the breaker so they can match the correct unit.

The GLS moved from the X166 generation (2016–2019) to the X167 generation (2019 onwards), and the two generations use significantly different electrical architectures, so the EIS or ignition control modules are very unlikely to be interchangeable across that boundary. Even within the same generation, Mercedes EIS units are typically coded to the vehicle and may require programming to the new car regardless. Always confirm with the breaker that the donor part matches your exact registration, and factor in that EIS coding by a specialist is usually required after fitting.

Trim level alone does not determine which EIS or ignition module is fitted to a Mercedes GLS — what matters is the generation (X166 or X167), model year, and the specific electrical specification of the donor vehicle. An AMG Line or standard GLS of the same generation and year should use the same ignition-related electronics, though the AMG 63 may carry additional performance control modules that differ. Confirm against your registration with the breaker rather than relying on trim name alone.

On a keyless GLS, a key fob not being recognised is more likely to point to a flat key battery, a faulty key fob itself, or an issue with the antenna modules or EIS unit rather than a traditional ignition switch — because no such switch exists on this model. Before buying any used parts, it is worth having the fault codes read by a Mercedes specialist, as the diagnostic output will usually identify whether the fault lies with the EIS module, the antenna ring, or the key itself. This saves you from purchasing the wrong component from a breaker.

Physically swapping an EIS module from a breaker car is possible, but the unit will almost certainly need to be programmed or synchronised to your vehicle's immobiliser and key fobs by a Mercedes specialist or auto locksmith before the car will start. Fitting an uncoded used EIS module without programming will typically leave the car immobilised. Factor the cost of coding into your budget when getting quotes from breakers, and check whether the breaker can supply any existing key fobs that were paired to the donor module, as this can sometimes simplify the process.