how to fix the weak airflow in my BMW 3 Series E90/E91 (2005-2012) AC

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Ensure the vehicle is parked on a level surface and the engine is off.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Replace Cabin Air Filter

• Tools Required: Phillips screwdriver, flathead screwdriver
• Steps:
  1. Remove the glove box by unscrewing screws and detaching any clips.
  2. Locate the cabin air filter housing behind the glove box.
  3. Remove the old cabin air filter and clean the housing of any debris.
  4. Install the new cabin air filter, ensuring it is oriented correctly.
  5. Reassemble the glove box.

3. Inspect and Replace AC Blower Motor (if necessary)

• Tools Required: Socket set, multimeter
• Steps:
  1. Access the blower motor by removing the lower dash panel.
  2. Disconnect the electrical connector from the blower motor.
  3. Test the motor with a multimeter to ensure it is receiving power.
  4. If the motor is faulty, remove it by unscrewing the retaining screws.
  5. Install the new blower motor and reconnect the electrical connector.
  6. Reassemble the lower dash panel.

4. Recharge AC System (if refrigerant is low)

• Tools Required: Refrigerant gauge, AC recharge kit
• Steps:
  1. Connect the refrigerant gauge to the low-pressure service port.
  2. Check the pressure readings and determine if the system needs recharging.
  3. If low, follow the instructions on the refrigerant can to add refrigerant.
  4. Monitor the system while recharging to avoid overfilling.