My G-Drive W/ Thunderbolt doesn't seem to turn on?

I just purchased a new G-Drive 4TB with thunderbolt and after hooking up the AC adaptor it doesn’t seem to turn on with the powerswitch. I have other G-Drives and they all light up once I turn them on. What am I doing wrong?

So I think I just figured it out I have had one for a month now and I notice that if I don’t have the drive plugged into my computer the power light doesn’t turn on. I have a 2011 Macbook air and with only one thunderbolt port I have to switch between my monitor or my G-Drive. If the drive was on and I disconnect it after dragging it to the trash the light turns off, plug it back in and the light turns on. I guess it needs to be plugged in. Hope this helps you.