Mercedes-Benz W204 (C300/C350) & W212 (E350) 8-Piece Front Window Regulator Repair Kit

Mercedes-Benz W204 (C300/C350) & W212 (E350) 8-Piece Front Window Regulator Repair Kit

This is an 8-piece electric window regulator repair kit, cross-referenced to OE numbers A2127201679 and A2127201579, built for the W204-chassis Mercedes-Benz C300 and C350 (2008-2014) and the W212-chassis E350 (2010-2015), front driver or passenger side. If your window has started dropping unexpectedly, moving slowly, or making grinding noises as it goes up or down, a worn regulator mechanism is a well-known issue on these Mercedes-Benz models.

Why a Repair Kit Instead of a Full Regulator Assembly

On many of these Mercedes-Benz window regulators, it's the plastic components inside the mechanism, not the electric motor itself, that wear out and fail over time, since the motor is generally built to last far longer than the smaller moving parts around it. This repair kit replaces those specific wear components rather than the entire regulator and motor assembly, which is why it's offered as an 8-piece kit rather than a single bolt-in part, and why it typically costs less than replacing the full assembly.

Key Features

• Cross-referenced to OE numbers A2127201679 and A2127201579
• Complete 8-piece kit for a full regulator mechanism repair
• Fits both driver and passenger side, front position
• Durable construction designed for long-lasting performance

Specifications

• Type: Window regulator repair kit
• Operating mode: Electric
• OE numbers: A2127201679, A2127201579
• Placement: Front, driver or passenger side
• Number of pieces: 8
• Manufacturer warranty: 1 year
• Condition: New

Compatibility

Fits the W204-chassis Mercedes-Benz C300 and C350 (2008-2014) and the W212-chassis E350 (2010-2015), front window position. Because Mercedes-Benz updated components across production runs, it's worth confirming the OE numbers above against your original regulator or reaching out with your VIN before ordering to help guarantee a correct fit.

Signs Your Window Regulator Needs Repair

A window that drops suddenly, moves noticeably slower than it used to, gets stuck partway, or makes a grinding or clicking noise during operation are all common signs of a worn regulator mechanism. Because a failing regulator can eventually leave your window stuck in the down position, addressing these symptoms before a complete failure helps avoid being left with an open window in bad weather, or having your vehicle vulnerable to break-ins with a window that won't fully close.

Why This Is a Common Repair on These Models

The plastic components inside these regulator mechanisms are a known wear point on this generation of C-Class and E-Class vehicles, which is why a repair kit specifically addressing these parts is widely available rather than requiring a full assembly replacement. Repairing the worn components directly addresses the root cause rather than replacing parts of the mechanism that are typically still functioning fine, which is also why this kit tends to be the more cost-effective route for most owners facing this issue.

Installation Notes

Installing this kit means removing the interior door panel to access the regulator mechanism, carefully supporting the window glass, replacing the worn components with the new kit pieces, and reassembling the mechanism before testing window operation. Because supporting the glass properly during this process is essential to avoid it falling and breaking, having an extra set of hands or a proper support tool makes this job considerably safer. Working slowly and testing the window's movement at each stage of reassembly also helps catch a misaligned component before the door panel goes back on.

Ordering Information

This window regulator repair kit is in stock and ships ready to install. Our Shipping Information page covers current timelines, and our Warranty and Returns pages explain what to do if anything isn't right on arrival. Not sure this matches your specific Mercedes-Benz and chassis? Our Request a Part page is the fastest way to confirm before you order.

Related Parts

This window regulator repair kit is listed in our Mercedes-Benz collection, along with our Electrical Parts collection, where you'll find other window and electrical components.