cruise control

 

The CC on/off does just that, if you turn the system off, you cannot use the right hand side buttons, and maybe press them accidentally. When you swich the engine off, it will also go back to off state, so you need to turn it on, and you set the speed you want to maintain. Then, when you brake or de/clutch the sytem goes to the equivalent of standby, and so when you press resume it will go back to your previous set speed, and you can use the + & - buttons to vary that speed.  You don't need to turn it back on again, in other words.

 

Hope that makes sense....