A circuit interfaces the brake, the drivetrain, and an accessory driven from the engine through a power take-off with the engine control so as to disallow application of the brake from discontinuing running of the engine at running speed set by the throttle control input whenever there is concurrence of a first input selecting placement of the accessory device in driven relationship to the power shaft, of a second input distinguishing that the transmission is in non-neutral position, and of a third input indicating vehicle speed is below a certain limit. The circuit allows a driver of the vehicle to apply the brake and operate the accessory without interrupting the set running speed of the engine so long the vehicle speed is below the certain limit.