CLK W209 window regulators & central locking dead? Door control unit A2098201926
“Window regulator and mirror no longer work on one side” – on a CLK W209 this is rarely a case for the window regulator motor alone. When several electrical functions of a door fail at the same time, the common denominator is usually the door control unit. It sits behind the door trim, is connected to the vehicle via the CAN bus and switches everything that works electrically in the door. Here you can read how to narrow down the fault and which number revisions fit.
Temic door control units for the front doors of the CLK W209 – the photos show the actual parts.
Symptoms
| Symptom | Likely cause |
|---|---|
| Window regulator, exterior mirror and central locking of one door all without function at the same time | Door control unit of this door failed or without power supply |
| Door does not respond to the remote control, the other side does | Door control unit or its connection to the CAN bus |
| Window moves up and down on its own when opening or closing the door | Malfunction in the door control unit |
| Control unit clicks, turn signals and entry light flicker, especially in the cold | Door control unit or contact problems at the unit |
| Diagnosis reports no communication with the door control unit | Door control unit, connector or wiring to the door |
| Only the window does not move, mirror and central locking work | More likely the window regulator motor or mechanics – the control unit still switches the other functions, after all |
| Door is hard to close mechanically or the latch does not engage | Not a case for the control unit, but for the lock or latch – see guide W124 door lock faulty? Symptoms, testing & solution |
Causes
The door control unit controls all electrical functions of its door: window regulator, exterior mirror adjustment, central locking, door lighting and switch block. In the driver's door, the remaining window switches are also routed through the unit. This concentrates many loads in one place – if it fails, several functions are affected at once.
The first W209 cars are now over 20 years old. The unit sits in the door, which is moved every time it is opened and closed, and is exposed to temperature changes. That failures or crackling occur especially in the cold fits this installation location. Add to that the number revision: Mercedes updated the units several times over the production period, left from A 209 820 01 26 via 21 26 to 19 26, right from 12 26 to 22 26 and currently 20 26.
Testing it yourself
- Compare the other door: If window regulator, mirror and central locking work on the other side, a central fault is unlikely – the problem lies in the affected door.
- Test functions individually: If only the window fails but mirror and central locking work, this points more to the window regulator motor or mechanics. If all functions of the door fail together, that points to the control unit.
- Observe cold behavior: If the unit audibly crackles or the turn signals and entry light flicker in cold temperatures, make a note of it – it helps to narrow down the fault.
- Read out diagnostics: If the tester reports no communication with the door control unit, first check the connector and wiring transition to the door, then the unit itself.
- Read the number on the unit: Remove the trim, open the flap in the insulation and note the Mercedes number (A 209 820 … 26) and the Temic number. Only with these can the matching replacement unit be determined reliably.
You proceed in a similar way with a seat adjustment that has stopped working, which we describe in the guide W210/W208 seat adjustment not working? Switch A2108209210 – there on the predecessor CLK W208.
Solution
Once the door control unit is confirmed as the cause, replacing it with a genuine unit with the matching number revision is the proper way. We offer used genuine Temic door control units for the front doors of the CLK W209 – each as a pair from one vehicle, genuine parts, not aftermarket. The price is a uniform 229,00 € per pair; eight pairs in various number combinations are currently in stock.
Available combinations include left 19 26 / right 20 26 (Temic 353380 / 353386), left 21 26 / right 22 26 (Temic 355224 / 355225), left 19 26 / right 22 26 and left 21 26 / right 12 26.
Condition: Used, housing with normal signs of use, partly handwritten markings from the dismantler, connector sockets clean, retaining clips present. Two units are supplied without cable and connector.
Important – not to be confused with: The units are intended for the front doors of the CLK W209. Compare the number on your own unit before buying. If in doubt, send us your VIN (chassis number) via the contact form, and we will check the assignment.
Door control unit pair L+R
left A 209 820 19 26 · right A 209 820 20 26
229,00 € / pair
View offer →
Door control unit pair L+R
left A 209 820 21 26 · right A 209 820 22 26
229,00 € / pair
View offer →
Door control unit pair L+R
left A 209 820 19 26 · right A 209 820 22 26
229,00 € / pair
View offer →
Door control unit pair L+R
left A 209 820 21 26 · right A 209 820 12 26
229,00 € / pair
View offer →You will find more pairs and number combinations in our entire parts range.
Compatible vehicles
| Model series | Models |
|---|---|
| CLK Coupe C209 (2002–2009) | CLK 200 Kompressor, CLK 200 CGI, CLK 220 CDI, CLK 240, CLK 270 CDI, CLK 280, CLK 320, CLK 320 CDI, CLK 350, CLK 500, CLK 55 AMG, CLK 63 AMG |
| CLK Convertible A209 (2003–2010) | CLK 200 Kompressor, CLK 200 CGI, CLK 240, CLK 280, CLK 320, CLK 320 CDI, CLK 350, CLK 500, CLK 55 AMG, CLK 63 AMG |
| Installation location | Front doors left and right – Coupe and Cabriolet with the same numbers |
FAQ
Where is the door control unit located on the CLK W209?
In each case inside the front door behind the door trim, behind a flap in the insulation. It is held at the top by two latching tabs and does not sit on the window regulator motor.
Do the door control units fit Coupe and Cabriolet?
Yes. CLK Coupe C209 and Cabriolet A209 use the same numbers for the front doors. Still, compare the number on your own unit.
Which part number replaces which?
On the left the sequence is A 209 820 01 26 → 21 26 → 19 26, on the right A 209 820 12 26 → 22 26. The current order number on the right is A 209 820 20 26. The newer number in each case replaces the older one.
Why are the door control units sold as a pair?
Both units come from one vehicle and have a matching hardware and software revision. The price of 229,00 € applies to the pair of left and right unit.
Are cable and connector included?
No. Two door control units are supplied, front left and front right, without cable and connector. The connector sockets are clean and the retaining clips are present.
KFZTeile-Thot is a specialist company for tested and refurbished Mercedes parts with its own test benches and has over 1,000 positive eBay reviews. Are you unsure which door control unit fits your CLK? Call us: +49 179 8991069 (Mon–Fri 8 am–6 pm) – or use our contact form.