I don't have to deal with commuter type slow traffic so mine never seemed to get to the switch point, so I have to force the issue to get it to activate the circuit. I had an early Suzuki gt750, aka known as the water buffalo, with a big radiator and an electric fan, it never activated either, it didn't need to, my later 1976 water buffalo, Suzuki had deleted the fan altogether as they deemed it unnecessary. I guess the brick's fan, when in slow traffic, will kick on after a couple of minutes, but the system seems up to the task and cycles on and off as expected.