Final answer:
U-Haul towing equipment consistently uses a 4-flat wiring harness, which is a standard for basic lighting functions necessary for towing.
Step-by-step explanation:
All U-Haul towing equipment uses a 4-flat wiring harness. This type of harness includes four wires bundled together that correspond to the basic lighting functions: tail lights, brake lights, right turn signal, and left turn signal.
It's a standard connector for towing and is known for its simplicity and ease of use. When using U-Haul trailers, it is crucial to ensure that your vehicle is equipped with this type of connector. If your vehicle does not have a 4-flat wiring harness installed, U-Haul locations often offer services to install the harness so you can safely tow your trailer.