my BMW 3 Series F30/F31 (2012-2019) AC blows warm air, how can I fix it?

Solution

1. Preparation

• Gather the necessary tools and parts.
• Park the vehicle on a level surface and ensure the engine is off.
• Disconnect the battery to prevent electrical shock.

2. Recharge Refrigerant

• Tools Required: Refrigerant gauge, refrigerant canister, safety goggles, gloves.
• Connect the refrigerant gauge to the low-pressure service port.
• Start the engine and turn the AC to the maximum setting.
• If refrigerant is low, add refrigerant according to the manufacturer's specifications (usually R-134a).
• Monitor the gauge to ensure it reaches the correct pressure range (typically 28-40 psi).

3. Inspect and Replace Components

• Tools Required: Wrench set, socket set, screwdrivers.
• Inspect the AC compressor for leaks and unusual wear; if damaged, replace it.
• Replace the cabin air filter if it is clogged:
  1. Locate the cabin air filter housing (usually behind the glove box).
  2. Remove the housing cover and take out the old filter.
  3. Install the new filter in the correct orientation.

4. Test AC System

• Reconnect the battery.
• Start the engine and turn the AC on to the maximum setting.
• Observe the operation of the AC compressor and check for cool air blowing from the vents.
• If the system still does not work properly, further diagnostics may be needed, such as inspecting the expansion valve or evaporator.