If the machine is always on, it may be mis-wired. I connected the wires up wrong on a Silverado Deluxe I was refurbishing a few years ago with hilarious results. When I turned the vacuum off, the power nozzle, if connected, would come on, and when I turned the vacuum on, the power nozzle would shut off. It turned out to be an easy fix, as I had just reversed two wires, but it would have made for a fun practical joke.