A keyless entry system for an automotive vehicle allows operation of a vehicle device or devices without the need for an ignition key or other mechanical keys. A user can simply depress a single push-button or operate another suitable type of switch to activate the system and operate the desired vehicle device to the desired position. The system generally comprises a pocket-portable radio signal transmitter and a controller mounted on the vehicle and associated with the vehicle device. The transmitter has a small, long-life battery and the controller receives electric power from the vehicle battery. Power conservation for both the transmitter and the controller is achieved by activating them for limited periods in response to operation of the manual switch.