Install switch into car to kill the amp.?

I am trying to install a switch for my amp but I have a problem. I cut the REM wire from the back of stereo deck and ran it to the + pole on switch, I then took the REM from the amp side and connected to the ground on switch. The amp will not turn off when I kill the (turn off) amp, the led on the switch comes on but it won't kill amp. Now, should there be a ground to the switch?