why does my BMW 3 Series E90/E91 make a clicking noise when turning the AC on?

Solution

1. Preparation

• Tools Required: Socket set, OBD-II scanner, multimeter, flashlight
• Safety Warnings: Disconnect the battery before working on electrical components.

2. Inspect and Clean

• AC Compressor:

  • Remove the AC compressor cover if accessible.
  • Inspect the compressor for any debris or foreign objects lodged in or around it.
  • Clean any debris using a vacuum or compressed air.

• Blower Motor:

  • Remove the blower motor assembly from the vehicle.
  • Inspect for any obstructions or debris in the motor housing.
  • Clean the blower fan and housing thoroughly.

3. Replace Components (if necessary)

• AC Compressor:

  • If the compressor is damaged, disconnect the electrical connector and refrigerant lines.
  • Remove the mounting bolts and lift out the compressor.
  • Install the new compressor by reversing the removal steps and ensuring all connections are secure.

• AC Belt:

  • If the belt is worn, remove the old belt by loosening the tensioner.
  • Install the new belt according to the manufacturer's belt routing diagram.

4. Recharge AC System

• Connect the AC service manifold gauges to the service ports.
• Check and recharge the refrigerant to the specified level according to the vehicle's service manual.

5. Final Checks

• Reconnect the battery.
• Start the vehicle and turn on the AC to verify that the clicking noise has stopped.