There are several plugs that are around the circuit board. Depending on what you are missing the most common plug is the spark plug that is the larger plug that is attached to the circuit board.
There are several plugs that are connected to the Chevy Malibu on of the plugs is called an adapter that attached to the lights of the Chevy Malibu. This one of the larger parts.
There are many electrical plugs. Spark Plug is the most common plug. It might be missing. It is large and is plugged into the electrical board. You can buy it and replace it yourself also.