As the name suggests, these connectors are square, and manufacturers commonly use them for sensors or switches. Rectangular connectors appear in various areas of an automobile, such as the engine control modules. Automotive pigtail connectors come in various shapes and sizes: square, rectangular, and round. Each shape corresponds to a specific type of connection in your vehicle. These connectors can be a big help when you need to connect two wires, repair damage, or extend a. The first step in identifying an electrical connector is determining whether it's a plug or a receptacle. People often overlook these small components, essential for ensuring a secure and reliable connection in various applications.