[Joe Ross]

kOn makes both outputs 12v. In this case, the LED on the spike should be off, and since there's no voltage difference across your LED Ring, it should be off also. I'm not sure why the fuse trips when you go off, possibly one output is switching before the other and shorting.

When you reversed the cable, you made one output stay at ground, and the other switched to 12v. This turned the LEDs on.

If your other spike worked with kOn, it may have a dead output.