Here is the backside of the controller board. That’s the Bluetooth module, ILogic ILT254S. Pin 1 is for the external antenna. Pin 2 is ground. That cap needs to be rotated 90 degrees counter clockwise to switch the output to the external pin. This cap is an 0402, which means 0.04” long by 0.02” wide. Really fucking small! To move it (unsolder and resolder) you need really fine tips and a high quality soldering iron like a Metcal.