03–09 Mercedes CLK Window Regulator Repair Kit Guide (C209/A209)

The 03–09 CLK Rear Window Problem — and the $25 Fix

If you own a 2003–2009 Mercedes CLK — CLK320, CLK500, CLK550, CLK55 AMG, or CLK63 AMG, C209 coupe or A209 cabriolet — there's a decent chance a rear window has already gone slow, started climbing crooked, or dropped into the panel and refused to come back. It's one of the most common age-related failures on this chassis, and on a two-door where the rear glass has to seal against the top, a window stuck down isn't something you can live with.

The good news: in most cases the expensive parts of the regulator — the steel frame and the electric motor — are fine. What fails are the plastic components the mechanism depends on. That's the entire reason a repair kit exists.

How to Confirm It's the Regulator (Not the Motor or Switch)

  • Press the switch and listen. A whir, click, or grind with no proper glass movement = the mechanism has let go, motor is alive. That's the repair-kit scenario.
  • Glass rises crooked or stops partway = the mechanism has partially failed and is binding. Repair-kit scenario — do it before it drops completely.
  • Total silence from the switch = motor or electrical. A kit won't fix that; you need a complete assembly with motor, or diagnosis upstream at the switch and wiring.

Pick Your Side

The kits are side-specific. Left is the driver side, right is the passenger side, as seated in the car:

Both rear windows on these cars age on the same schedule. If one side has failed and the other is getting slow, doing both while the interior trim is already off is the move most owners wish they'd made the first time.

What the Job Involves

This is a realistic DIY for a patient owner with hand tools: interior trim off, glass supported and out of the way, the worn components swapped for the kit parts, then reassembly and a test before the trim goes back on. Set aside an unhurried afternoon the first time. Two things matter more than speed — support the glass before you free the mechanism (it will drop the moment tension is released), and keep every fastener organized as it comes off. See the kit listing for exact contents; if you open the door up and find a bent frame or a dead motor instead, stop there and step up to a complete assembly rather than forcing the kit onto damaged hardware.

Repair Kit vs. Complete Assembly on the CLK

For the 03–09 C209/A209 cars, the kit is the first move whenever the motor works. For the previous-generation 99–03 CLK (W208), we stock complete used OEM assemblies instead — rear left, part 208 670 01 03 and rear right with motor, part 208 670 02 03. The full decision logic between kit and assembly is in our window regulator repair-vs-replace guide.

While You're In There

With the trim already off, it's the ideal time to refresh the other interior wear points this generation shares — worn button faces and switch surfaces are covered by our interior button repair kits, and the wider parts catalog for these chassis lives in Interior Trim & Accessories and OEM & Replacement Parts.

Front regulator on your CLK acting up instead, or need a side we don't show in stock? Send us your year, model, and VIN and we'll source it.

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