Why do I have the butting twice to start the engine ?

Some vehicles do not supply power to the brake switch when the vehicle is in the OFF state. The Brake input becomes active only when the vehicle is in ACC or Ignition (ON) state. If so, look for an alternative brake output signal from the vehicle or install a separate 12V brake supply wire to the brake switch. Connect to the brake switch supply side and diode isolate the existing brake supply wire (Diode band towards the switch side of the existing wire).