If it has a door popper kit, you should see a spring-loaded plunger thingy (or even two of them) mounted on the black trim of the rear hatch are on the right side (as you look in). If that's what it is, you would definitely hear the sound of the solenoid when you press the button.

Make sure you have the ignition in the ON position while you try to figure out what that switch does, as whatever it is may be wired in to a switched circuit.

Good luck!