yea... the same one that send the signal to the amps etc to turn them on and off with the stereo.
I had my pioneer stereo stolen and was wired in via the remote lead and all was fine.... However, just bought a new pioneer stereo and hooked it all up the same via the same remote lead in the harness and the amps stayed on when the stereo was off, so, switched the connection to the yellow and red stripe wire which turns on with the cars ignition. All is well and working now.