The AirBolt GPS has LED which lights up the Humming Bird in front of the device. Here is what the colours mean
On button press, you will see a red light blink.
Blue light - fading in and out = looking for cellular signal/acquiring cellular information.
Yellow light - flashing three times = network error, not able to connect.
Green light - fading in and out = looking for GPS (to obtain GPS signal, best to place outside with view to sky).
DURING CHARGE -when your GPS is plugged into the USB-C: