How to turn off AC fan mode outside air?

Each car’s air conditioning system has two modes of taking inside and outside air, which helps you control the air conditioning system according to your preferences. The AC fan mode outside air is preferred by many people because the feature of drawing air from the outside helps the air in the car become comfortable when you travel long distances. However, this model also has limitations that make users want to turn off this feature. So how to turn off AC fan mode outside air? Find out the most detailed information in the article below!

Advantages and disadvantages of the AC fan mode outside air

The function of taking outside air is simply understood as a mode to collect air outside the environment, sucked in by the blower, filtered to retain dirt, and then blow clean air into the car.

AC fan mode outside air system-


  • When you first start the car, outside air mode accelerates the exchange of cabin air, helping you feel cooler inside. Especially when leaving the car for a long time outside will make the air in the car become secret.
  • When making long trips, it is advisable to actively use outside air every 30 minutes to freshen the cabin and ensure the amount of oxygen in the car. This helps the occupants to feel more comfortable, reducing the feeling of fatigue when sitting for many hours in the car.
  • Helps the air in the car become fresher and cooler when going through places with fresh air.


  •  When using the outside air intake mode in wet or rainy weather, it will cause moisture to enter the cabin leading to mold.
  • The air in the car is very easy to be polluted when going through areas with a lot of unpleasant odors, dust, etc…

Although there are many advantages, the limitation of this feature also makes many users feel uncomfortable. Therefore, many people want to turn off the AC fan mode outside air. How to turn off this function? Find out below!

Instructions on how to turn off the external ventilation function

Before proceeding to turn off the function by software, we need to check the parts of the air conditioning system: blower, connected devices, buttons, wires, compressor… After checking the whole thing After the hardware of the air conditioner is finished, if the error is not detected here, then diagnose it through the software.

So you need to prepare the following devices

  • Vediamo or DTS Monaco software: These are two software for engineers to use for offline programming and coding when replacing a certain control box on the car; Read, clear errors, reset control box; Change the previous control box setting value parameter,…
  • Device c4 (Required): This is a device that supports in-depth diagnostics of vehicle systems.

Support device to disable TPMS

  • Mercedes Coding Guide Book Vediamo-DTS Monaco: see more

Detailed steps to proceed:

Step 1: Park the car in a flat position for easy operation. Then check the device and software
Step 2: Connect the device and software to the car
Step 3: Open Xentry software and conduct diagnostics

Xentry diagnostic software
Open Xentry software and perform diagnostics

Step 4: Connect the HVAC control box (CBF) in the Mercedes
Step 5: Encryption off function
Step 6: Finish and check again.

You can refer to more troubleshooting videos on Eurocartool’s youtube channel here: Car Diagnostic Software

Support from Eurocartool

When turning off a certain feature, it needs to be done with devices and software, so to ensure that there are no mistakes in the implementation process, you need to learn and do a lot. If you are facing this situation and want to turn off this function of taking outside air but do not know the operation. Immediately contact the technical team at Eurocartool for the fastest advice and support.

Especially at Eurocartool !!!

  • 24/7 technical support service: Diagnosis, Coding-programing via TeamViewer
  • 1-year software warranty and lifetime support
  • Free repair documents for new car models with full video instruction
  • Limited edition manual was written by Eurocartool’s technicians during the process of coding and programming offline Mercedes- Audi -….- BMW

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Fanpage: Car Diagnostic Software


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