Check fan modules' connections

  1. Disconnect the power cord.
  2. Remove the 3.5x16 screws (4 pcs) and take out the fan module.
  3. Check that the fan DC cord and the DC extension cord are securely connected.
  4. Reinstall the fan module.
  5. Repeat steps 2 to 4 for the other fan module.
  6. Connect the power cord.