Amazon: 4 pin wiring harness CZC AUTO Trailer Wiring Harness Kit 4-Way Wishbone Style, Y Style 18AWG Pure Copper Core Color Coded Wire with Standard 4-pin Flat Plug Connector, 4' Amazon: 4 pin trailer connector Amazon: 4 pin trailer connector. Skip to main content. CURT 58671 Vehicle-Side and Trailer-Side 4-Way Round Trailer Wiring Harness Connectors, 4-Pin Trailer Wiring. 4.3 out of 5 stars 32. $12 $ 12. 09. Get it as soon as Wed, Oct 9. FREE Shipping on orders over $25 shipped by Amazon.