4-Zone Climatronic: Center and Rear Vents Blowing Cold + Clicking Noise

Jan 19, 2025 | 05:18 PM

kristiyan

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E200 CDI w211 and ML320 CDI w164

4-Zone Climatronic: Center and Rear Vents Blowing Cold + Clicking Noise

Hey everyone,

I’m having some issues with the 4-zone Climatronic system in my 2003 Mercedes W211 Here’s what’s happening:

Problem:
- The side vents blow hot air, but the center vents (front) and rear vents blow cold air even when the temperature is set to max (33°C).
- The rear zone stays cold regardless of the settings.
Diagnostics:
- I scanned the system using DAS, and it shows a fault with M2/12 (left center flap actuator), which is flagged as mechanically faulty.
- There’s also a clicking noise from time to time coming from the dashboard
What I’ve Checked So Far:
- Coolant level is fine, and the system seems to be circulating properly.
- All temperature and airflow settings on the climate control panel have been synced, but no improvement.
- No errors are shown for the rear zone actuators.
My Questions:
- Could the faulty M2/12 actuator be causing the cold air issue in the rear vents as well?
- What’s the best way to inspect and confirm if the blend doors actuators are stuck or broken?
- Should I replace M2/12 first and see if that fixes both the center and rear issues?

Any advice on troubleshooting this further or steps for replacing the actuator would be greatly appreciated.

If someone has experienced a similar issue, I’d love to know how you resolved it!

Thanks in advance!

Cheers,

Kristiyan

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