Trailer Wiring - Plugs and Sockets
May 7th, 2015
  By Bert Camp
  Customer Service Representative at ReeseHitches.com


Hello to my fellow towing friends. Today I wanted to talk about the different kinds of trailer wiring plugs and sockets on the market and what kind of functions they offer.  There a lot of differences in trailer and tow vehicle plugs and sockets; so be sure to familiarize yourself for what you need or what you currently have.  Have fun learning!  
 
2-Way Flat Plugs – Part numbers 74285 Car End and 74275 Trailer End.  The functions they offer are power and ground. It’s a pretty straight forward product. This kind of plug set-up is to provide a plug-in connection for a 12 volt accessory like a back-up camera , interior lights, battery charge, etc.
 
3-Way Flat Plugs – Part numbers 74385 Car End and 74375 Trailer End.  The functions they offer are power, brakes and ground with NO turn light functions. This type of plug is designed to offer an auxiliary electrical line for your towing needs. 
 
4-Way Flat Plugs – Part numbers 7275 Car End and 7285 Trailer End.  The functions they offer are right turn signal (Green), left turn signal (Yellow), tail light (Brown) and ground wire (White).  This is the most common of all wiring kits on the market because it offers the basic four functions. Turn signals, stop lights and running lights.  The 4-way flat harness is for 12V systems only.  
 
Please bear in mind that some vehicles require a Tail Light Converter or a powered converter known as a ModuLite®. We will go over tail light converters and what they do later in another blog post.  Also, many newer vehicles have factory plugs in the rear where a T-connector can be installed. Click Here to see if there is a T-connector available for your application. You’ll save yourself a lot of time and energy.
 
4-Way Round Heavy-Duty – Part numbers 11-404 Car End and 11-402 Trailer End. The functions they offer are just like the 4-way flat plugs listed above but this is a heavy-duty die-cast model that is designed for 12-24 volt systems.  This style of plug must be hardwired by inserting wires into the back side of the plug. Click on the following links to see wire and terminal locations on the front and back of the car end socket, or the front and back of the trailer end plug.  
 
5-Way Flat Plugs – Part numbers 2309 Car End and 2409 Trailer End.  The functions they offer are stop, turn, tail, auxiliary power and ground.  These plugs are designed for boat trailers that are equipped with hydraulic brakes/surge brakes.  The fifth wire is for disengaging the trailer's brake actuator while backing up, which shuts off the trailer's brakes.
 
6-Way Round – Part numbers 11-609 Car End and 11-604 Trailer End. The functions they offer are: Right turn, left turn, tail lights, electric brakes, battery and ground.  This style of plug must be hardwired by inserting wire into the back side of the plug. Click on the following links to see wire and terminal locations on the front and back of the car end socket, or the front and back of the trailer end plug.  
 
7-Way with Flat Pins (RV-Style) – Part numbers 12-707 Car End and 12-706 Trailer End. The functions it offers are: Right turn, left turn, tail lights, electric brakes, battery, auxiliary and ground.  This style of plug must be hardwired by inserting wire into the back side of the plug. Click on the following links to see wire and terminal locations on the front and back of the car end socket, or the front and back of the trailer end plug.  

7-Way with Round Pins – Part numbers 11-721 Car End and 11-702 Trailer End. The functions it offers are the same as shown above on the flat pin version.  This style of plug must be hardwired by inserting wire into the back side of the plug. Click on the following links to see wire and terminal locations on the front and back of the car end socket, or the front and back of the trailer end plug.  

Color Codes – Please keep in mind the color codes shown here in these pictures are the colors the plug manufacturer uses to identify the different functions of each plug.  These colors may or may not be the same as the wire colors on your particular vehicle or trailer.  Be sure to verify the function and color of each wire in your system before you begin.

As always, if you need help please give us a call at 1-877-509-0719.  We'll be glad to assist however we can.
at 877-509-0719. We can handle most any question you have about - See more at: http://www.reesehitches.com/news.php?pid=29&p=&search=&cat_id=0#blt
at 877-509-0719. We can handle most any question you have about - See more at: http://www.reesehitches.com/news.php?pid=29&p=&search=&cat_id=0#blt
at 877-509-0719. We can handle most any question you have about - See more at: http://www.reesehitches.com/news.php?pid=29&p=&search=&cat_id=0#blt

Happy Trails!

Bert