The following diagram conforms to the standard agreed upon by vehicle manufacturers and companies producing the trailer connectors. This will allow you to hook up your old trailer to a new truck, or bring home a new commercially built trailer without any wiring hassles. Backup lights can be hooked up to 7. Auxiliary Yellow. This is also the view of the exterior trailer connector pins.
A number of standards prevail in North America , or parts of it, for trailer connectors , the electrical connectors between vehicles and the trailers they tow that provide a means of control for the trailers. On cars and light trucks listed below as Light Vehicles there is no formal standard, instead there is a wealth of contacts with more or less accepted standard. However, you can not be entirely sure until you have measured the current connector on the vehicle and trailer that they fit each other. Note that different color coding can be used for certain functions, which means that you can not trust the colors mentioned here without measuring the contact and wiring from case to case. In some cases - as in the flat 4-pin or 5-pin connector - it is fairly obvious which color that is connected to which pin.
Whether you're installing a new trailer light circuit in your car or truck or trying to troubleshoot trailer wiring that is not working, you'll need to understand what each wire in the trailer wiring harness does, where it likely goes, and why it may not be working well. This diagram shows the colors of a basic trailer wiring setup as well as what each wire is supposed to be connected to. While it's never a good idea to dive into a wiring project blind, trailer wiring is actually very simple to work on and troubleshoot. For the most part, the wiring harness that operates your trailer lights is a closed system.
Video tutorial on how to wire trailer lights. So here I have an older trailer which needed some work, along with re-wiring the lights. This is a fairly simple setup, no license plate light, or clearance lights. Be sure to check with your local laws in order to determine what is required for a lights. This also makes it much easier to work on, so if you have a smaller trailer and can do this, I would definitely recommend it.