If your ION speakers are the same model, or if they are listed within the same tier on the ION Compatibility Chart, then the problem may be that your secondary speaker is trying to connect to a device.  The following steps will prepare your secondary speaker for wireless linking:

  1. Decide which speaker is going to be your Primary speaker and turn it off.
  2. With the Secondary speaker on, make sure that your device is not connected to it.
  3. If your device is connected to the Secondary speaker, disconnect from your phone's Bluetooth settings and, if possible, select "Forget Device" to be sure.
  4. Turn the Primary speaker back on and allow it to connect to your device.
  5. Set the Primary speaker into Link mode.  If voice prompts are on, you will hear an indication that this is the Primary speaker.
  6. As long as no device is connected to the Secondary speaker, you will now be able to set it to Link mode and it will connect to the Primary speaker.  This may take up to a minute.