LG DSH7Q Owner's Manual page 8

Checking the connection with the LED on the front of the wireless
subwoofer
You can check the connection status by looking at the LED on the front of the wireless subwoofer.
LED Colour
Blinking green
Green
Red
Off
8
Status
Connecting in progress
Connected successfully
Bad connection, or the subwoofer is in standby
Power cable not connected