A battery backup system for providing uninterrupted power to components within a vehicle electronic control module (ECM). The backup system comprises a header connector with a recessed region for the battery. A connector plug is plugged into the header connector over the battery to cover the battery and shield the battery. The backup battery is disposed within the recessed region in contact with electrical contacts extending from the housing of the ECM, the electrical contacts providing a connection between the backup battery and an electronic component needing a backup power supply. Additional terminals on the connector plug can be used to provide power to the backup battery. The backup battery can be in a closed circuit with the electronic component, or the backup battery circuit can be switched to form a closed circuit with the electronic component when the electronic component no longer receives power from the primary power source.