Hooking up LED pnterior lights?

[Fuzz]

I have a little project going this morning. I am wondering if my idea that i have will work. I have led lights, and a toggle switch. im wanting to hook them together so i can ( I bet you have already figured out this) turn them on and off.

This is what i have:

My Idea:
Cut the end off,splice in the toggle switch, ground the wires to where my amp is grounded. Will this work? Do i need to run a seperate ground wire to the toggle switch?

A few more pics:

 

[James86]

Only the positive will run to the switch, the ground is simply grounded to the truck. However, the point of that big plug is that there is a fuse in it in case somethign goes wrong and it wouldn't be a bad idea to have a fuse for any electrical device.

 

[srteach]

Most cheap LED lights are small voltage LED lights. Check the voltage output of the plug to see if the output is 12V. If it is, splice away. If it is not, you have to limit the current and voltage that you put into the lights when you splice it. You can usually do this by splitting the plug and using the guts of the plug in the supply side of the circuit.