Mercedes AC Reset: Multiple Methods

Mercedes-Benz AC Reset Guide: If your Mercedes-Benz air conditioning (AC) system is not blowing cold air or behaving inconsistently, performing an AC reset may help restore normal function. This reset process recalibrates the blend doors and sensors in the climate control system.

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✅ When to Perform an AC Reset

• AC not cooling properly

• Blower fan not responding

• Unusual airflow or temperature behavior

• After battery disconnection or replacement

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🚗 Applicable Models

This reset procedure applies to many Mercedes models equipped with automatic climate control, including:

• C-Class (W204, W205)

• E-Class (W212, W213)

• S-Class (W221, W222)

• GLE, GLC, GLS, ML, etc.

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🔄 Step-by-Step AC Reset Procedure

1. Turn on the Ignition
   Insert the key and switch to position II (do not start the engine). For push-button models, press once without stepping on the brake.

2. Mercedes AC Reset: Set AC Controls to Default

   • Set temperature to "LO" or 16°C on both driver and passenger sides.

   • Set fan speed to AUTO.

   • Make sure AC and air recirculation are ON.

3. Press and Hold Two Buttons
   On the climate control panel, press and hold the "Rest" and "AC" buttons simultaneously for about 10-15 seconds.
   (On some models, use "Defrost" and "Recirculation" instead.)

4. Wait for LED Flash or Audible Signal

   • You may see the LEDs on the AC panel flash, or hear a beep.

   • This indicates that the system is performing a self-test and reset.

5. Leave the System for 30–60 Seconds
   Let the system run its calibration. Do not touch any buttons.

6. Turn Off Ignition
   After the reset completes, turn off the ignition for a minute.

7. Restart the Vehicle
   Start the engine and test the AC system to check if normal operation is restored.

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🛠️ Alternative: Fuse Reset (If Button Reset Fails)

You can also reset the AC system by pulling the climate control fuse for a few minutes and reinserting it.

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⚠️ Note

• If the reset doesn't solve the issue, the problem may be due to a faulty compressor, refrigerant leak, temperature sensor, or blend door actuator.

• Consider using a diagnostic tool (OBD2 scanner) to check for AC-related fault codes.

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If you tell me your exact Mercedes model and year, I can tailor the steps more specifically.