I think my runs from the radio fuse.Anytime I turn the radio on the amps come on.Turn off the radio amps go off.Good if you have lights on your amp that may pinpoint you as the loud car when the cop heard it but wasn't sure where it came from and you have time to turn off the radio.Also good if it's at risk of overheating as you can turn the radio off til it cools then back on without having to turn the car off.