This article describes the Remora LED behaviour. 

Further Information
OffIf the LED is not on at all, it is likely that the battery is flat, or that the device is asleep. Measure the battery voltage with a multimeter. If there is charge and you wish to see some activity reset the device by removing and replacing the batteries.
From power-on-reset, LED flashes for duration of startup connect, fix, connect. Or until 10 min have passed.
After a reset of the device, the LED will flash. It will continue to flash until it has completed its startup sequence of: connect to server (4Hz flash); get a GPS fix (1Hz flash); and reconnect to the server (4Hz flash). If the connections are not successful, this will timeout after 10 minutes.
After first sleep - off    After the startup sequence has completed (connect, fix, connect) or after 10 min, the LED will be switched off. No LED flashes will occur, until a power-on-reset, or tamper.
On tamper - single flashThe LED will go on for 200ms when a tamper is detected.
In Recovery Mode - flashes in tripThe LED will flash once every 5s during trips in recovery mode.