What can I say? Mine DEFINITELY activates as soon as I switch it on. You can "feel" it. No foot tap needed. If I accelerate, I do not change the braking action. I have to turn off the switch if I am going to get out of the mode and move to a mode where I do not feel the braking action.
So does mine, that is what the BrakeSwitch prevents by requiring a tap of the brakes to activate the exhaust brake.
The article that Blueblood gave us at the top also instructs when to turn on the switch, so while not directly expressed, the implication is that the normal running position is off. What the BrakeSwitrch does (amoung other things) is to avoid reaching for that switch when you need exhaust braking, just tap the brake.
It also refers to the mileage implications. You will improve your mileage because the coach will coast more until you touch the brake.
These points of confusion have come up in other threads. I believe there are several kinds of braking systemsbeing discussed. Likely everyone here is correct, but from the viewpoint of different coaches and configurations. When I get to the factory I will find out more about this subject.