Abstract: A vehicle such as a van has a sliding door movable between open and closed positions. An electric power source, a door drive switch and electric door drive apparatus are connected in series on the vehicle body to move the door when the switch is closed. Contacts on the vehicle body and door engage as the door nears its closed position; and the door contacts are connected through circuitry, such as an unlatch motor armature, having a first resistance. One of the body contacts is connected to ground and the other is connected, through circuitry including a resistor of greater resistance than the unlatch motor armature, to a junction of the door drive switch and the electric door drive apparatus. An output terminal connected between the resistor and the other body contact provides a signal voltage having different levels depending on engagement of the body and door contacts.