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Curt 4-Pole Flat Vehicle Wiring Harness w/ Mounting Bracket

Curt 4-Pole Flat Vehicle Wiring Harness w/ Mounting Bracket

Item # C58345
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Wire your vehicle to tow a trailer with this universal, splice-in wiring kit. Includes 4-way flat connector, bonded wire, mounting bracket, and necessary hardware. Designed for use with 2-wire electrical systems. Lowest Prices for the best trailer wiring from CURT. Curt 4-Pole Flat Vehicle Wiring Harness w/ Mounting Bracket part number C58345 can be ordered online at or call 1-800-496-5010 for expert service.
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  • Reviews (37)
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CURT Trailer Wiring - C58345

  • Trailer Connectors
  • Vehicle End Connector
  • 4 Flat
  • Plug and Lead
  • CURT

Wire your vehicle to tow a trailer with this universal, splice-in wiring kit. Includes 4-way flat connector, bonded wire, mounting bracket, and necessary hardware. Designed for use with 2-wire electrical systems.


  • 4-Way flat trailer connector at the back of your vehicle powers your trailer's signal lights
    • Compatible with 5-pole, 6-pole, and 7-pole adapters (sold separately)
  • Rubber-molded connector and bonded wire provide maximum durability
  • Simple installation
    • Hardwires to existing wiring
    • Includes quick-splice connectors for easy splicing of wires
  • Electrical mounting bracket lets you attach connector to your vehicle


  • Wiring harness length: 60"
  • 1-Year limited warranty

58345 Curt 4-Way Flat Connector Socket Kit

California residents: click here

Video of Curt 4-Pole Flat Vehicle Wiring Harness w/ Mounting Bracket

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Curt Wiring - Trailer Connectors - C58345 Review

Speaker 1: Today, we're taking a look at the Curt 4-Pole Flat Vehicle Wiring Harness, with the included mounting bracket. This 4-way flat trailer connector can be used to add a new connector, or replace an older, damaged connector on your vehicle. It locates at the back of your vehicle to power your trailer's signal lights. It is compatible with 5-pole, 6-pole, and 7-pole adapters. Adapters are sold separately. This unit features a nice rubber molded connector, as well as bonded wire, to provide maximum durability.

It measures 60" long, and it's a simple installation. It hardwires to your existing wiring on the vehicle. It does come with quick splice connectors for easy splicing of the wires. Now, if you want to add more protection to the connection points, I recommend using heat-shrink butt connectors, which are sold separately, and available at unit also comes with your mounting hardware and the electrical mounting bracket. This lets you attach the connector to your vehicle.

That way, it's always accessible and easy to locate at the back of the vehicle, when you're ready to connect to your trailer. Now, this bracket has an overall width measurement, I measured from edge to edge, of 2-1/4" wide. Overall depth from front to back is 1-1/4" deep, and the overall height from bottom to top is about 1-3/4" tall. Those mount holes are separated on center by 1-11/16". When it comes to the wiring, you see it's a four wire design.

White wires are ground, yellow wires for the driver side turn and brake, green is for the passenger side turn and brake, and then the brown wire's for the taillights. That's going to do it for today's look at the Curt 4-Pole Flat Vehicle Wiring Harness with the included mounting bracket.

Customer Reviews

Curt 4-Pole Flat Vehicle Wiring Harness w/ Mounting Bracket - C58345

Average Customer Rating:  4.9 out of 5 stars   (37 Customer Reviews)

Wire your vehicle to tow a trailer with this universal, splice-in wiring kit. Includes 4-way flat connector, bonded wire, mounting bracket, and necessary hardware. Designed for use with 2-wire electrical systems.


Sometimes all you need is a simple bracket to hold a connection, instead of having a cable hang down...and this works perfect. I wanted something basic on my S10 that I could mount underneath to the bumper, next to my receiver hitch, to plug my PWC trailer connection into. I had no need for those large 7-way units (nor the space)...WORKED PERFECT!


Nice design, but the wires need to be about a foot or so longer for a Jeep Grand Cherokee.


Works as described. Easy to follow installation instructions.


Nice quality, good price


Seriously amazing product... I spent more time installing my trailer gate on the trailer than I did installing the wiring harness on my vehicle!! The instructions were clear, and installation was FLAWLESS!!!


Perfect. I've never seen a trailer plug like this. It saves me from dragging my old plug on the ground occasionally


Install was easy and item performs grea t.




Products were as listed - great quality and as always fast service!


Easy install, 15min and you're done.


Very easy to hook up and works perfectl y.


good quality installed very easy.


Very quick shipping and items exactly as described.
Thank You!


Bracket seems heavyweight good material


I was very happy with everything and would recommend this company to everyone


They always have what I’m looking for and delivery is always on time.



Item and Service was Great!



Great, prompt service. Would shop here again.



Exactly what I needed!





Show More Reviews

See what our Experts say about this CURT Trailer Wiring

  • Curt 4-Pole Flat Universal Vehicle Wiring Harness Wiring Size
    The Curt 4-Pole Flat Vehicle Wiring Harness # C58345 is constructed with bonded 16-gauge wires and durable molded rubber insulation. This kit is specifically designed for vehicles that have a 2-wire taillight system. This means that power for the turn signal and brake light are shared by the same wire on your vehicle. A No-Drill Mount for Electrical Mounting Bracket # 18140 can be used to allow you to fasten the wiring to your receiver.
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  • How To Add a Trailer Hitch To a 5th Wheel Trailer to Pull a Boat Trailer
    The Adjustable Width Trailer Hitch Receiver part # C13703 is what I recommend installing on a fifth wheel trailer due to its universal nature that allows it to be installed on pretty much any trailer. The Adjustable Width Trailer Hitch Receiver provides a 3,500 lb gross trailer weight capacity which would be around the limit. In regards to installation, the process is pretty straight forward and you can use the included brackets as your template for drilling. In order to provide lights...
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  • Correct Trailer Wiring Harness for 2006 Scion xB
    The Curt T-Connector Vehicle Wiring Harness # C56030 that you mentioned is the correct custom harness for your 2006 Scion xB. From what I could find, your vehicle's factory wiring system should have the brake and turn signals sent along separate circuits. This Curt harness includes a converter to combine these two circuits so that they're compatible with standard trailer wiring (which has the brake and turn signals sent along the same wire for each side). I'm not quite sure what you mean...
    view full answer...
  • Recommended Trailer Connector for 2020 GMC Sierra 1500
    I'd recommend the # HM40975 which would provide both a 4-pole and a 7-way connector. This is what GM uses as the OEM trailer connector. The HM40975 would plug into the round US car connector that is plugged into the knockout next to the license plate. remove the knockout, unplug the socket from the rear of the knockout and plug the connector into the socket on the back of the # HM40975. The connector I recommended includes the mounting bracket and mounting screws, although your truck should...
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  • How to Power Lightbar Without Plugging Into Factory Tow Package
    That is correct! Splicing straight into the tail light wiring is the only way to power a lightbar like # BLS-1103 without making your truck think the lightbar is a trailer. The tow package port in the rear only disables the rear features because it thinks you are towing a trailer. By getting your power from the lights themselves and leaving the factory port open, then it will be business as usual with all your safety features like the camera, sensors, etc. Carla gave great advice with...
    view full answer...
  • Will The Curt C13294 Fit My 2016 Mercedes GLE 450 AMG Coupe Hitch
    Yes the Curt trailer hitch receiver # C13294 will fit your 2016 Mercedes-Benz GLE. If you are going to haul a trailer you will also need a ball mount like the Curt class III # C45036 ,2 inch ball included. As well as a wire harness to power trailer lights, like the Curt 4-Pole Flat Vehicle Wiring Harness mounting bracket included. # C58345. If the trailer you are towing has electric brakes it will need a different harness like the Universal Wiring Harness with Brake Controller Harness...
    view full answer...
  • Recommended Trailer Hitch and Wiring for 1965 International Travelall
    Since there is no custom-fit hitch for your 1965 International Travelall, you will want to go with a universal hitch like the Draw-Tite Ultra Frame Service Body Trailer Hitch Receiver # 41990-07. The # C14082 is not confirmed to fit your vehicle. The Draw-Tite hitch has a 2" receiver and fits vehicle frames up to 44". This is a weld-on hitch so we recommend taking it to a certified welder for installation. For wiring you can use the # C58345 which also comes with a mounting bracket. If...
    view full answer...
  • Length of Wire on Curt 4-Pole # C58345 Trailer Wiring Harness
    The wiring harness you mentioned, part # C58345 is 60 inches or 5 feet long. Rather than using the quick connectors provided with the kit I'd recommend soldering the connections and sealing the connection with heat shrink tubing like # DW05452. If you don't solder, we carry heat shrink butt connectors that are almost as good, part # DW05744-5
    view full answer...
  • 2019 Ford Ranger LED Tailgate Light Causes Trailer Light Out Error Code and Disables Backup Camera
    I have a solution for you but the T-One Vehicle Wiring Harness with 7-Way Trailer Connector # 22124 will not work since it connects to the same tow package port your existing factory 7 and 4-way connector plugs into. When you plug in a tailgate bar, like # BLS-1103 (or any accessory that uses lights) into your factory wiring, it tells your vehicle that there is a trailer connected, which is why it disables the backup camera lines, as you mentioned. Otherwise, the sensors would constantly...
    view full answer...
  • How to Wire 3rd Stop Lamp in Camper Shell on 2021 Ford Ranger
    The # C58345 4 pole trailer wiring harness wouldn't be a good option, as the brake lamps and turn signals are carried on the same circuit. If you installed it that way, your 3rd brake lamp would blink along with the turn signal as well as illuminating with the brake pedal. There are a few ways to do this. The easiest way to do this would be to pull the 3rd brake lamp housing out of the rear of the cab and use a circuit tester like # 40376 to find which wire carries the brake lamp signal,...
    view full answer...
  • Can I Use Both The 7-Way and 4-Way At The Same Time?
    I have a solution for you, but you won't be able to use both the 7 way and 4 way plugs on the Hopkins # HM40975-11998 at the same time because the cover flaps do not allow for both to be open simultaneously. In order to plug both your 7 way and 4 way into the same plug you would need to use the Curt Trailer Connector Adapter # C57672 , which has the plugs side by side with dust caps that flip up to allow you to connect your plugs as desired. If you don't already have a wiring harness...
    view full answer...
  • Available Vehicle and Trailer Wiring Connectors
    I cannot recommend custom-fit trailer wiring for your vehicles without knowing their year, make, model and version but I can help you with basic 4-pole type connectors for both the vehicle and trailer. I linked pages for both types of connectors. For a trailer side 4-pole you can wire in to your trailer we have items like # W787274 and # 54000-026. For a vehicle side 4-pole we have # 18252 and # C58345 which includes a bracket. For a bracket only use # 18144. I also linked a helpful article...
    view full answer...
  • Can I Install A Trailer Hitch On My 2003 BMW X5?
    Yes, the two trailer hitches we carry that will fit to your 2003 BMW X5 are the Curt Trailer Hitch Receiver # C13162 and the Draw-Tite Max-Frame trailer hitch receiver # 75492. I recommend the Draw-Tite hitch it will be easier to install I have a link to the installation of the Draw-Tite hitch. If this is for towing trailers you will need a wire harness like the Curt 4-Pole vehicle wiring harness with mounting bracket # C58345 and a hitch ball mount and ball like the Curt Towing Starter...
    view full answer...
  • Trailer Brake Controller And Wire Harness For 2003 BMW X5
    I recommend the Curt Echo Wireless Trailer Brake Controller # C51180 it is set up as fast as you can plug it into your vehicle and trailer ends. Then you control it via Bluetooth from an app on your mobile device. The Redarc Tow-Pro Elite Trailer Brake Controller - 1 to 3 Axles - Proportional # RED44FR is a great choice for a brake controller if you want actual hardware and a knob to use instead of your mobile device. Your 2003 BMW X5 has many options for trailer brake controllers and...
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  • What All is Needed to Add an EZ Connector to a 2012 Expedition and Trailer?
    Switching over to the EZ Connector Magnetic 7-Way # 319-R7-01 will lose the 4 flat connection. However, I do have a couple solutions for you. First will be the Trailer Connector Adapter # 319-R7-54. This will adapt a standard 4 flat to work with the # 319-R7-01. If you preferred to keep a 4 flat plug, it will be a little more complicated, but not overly so. To do this, you will need to splice a 4 flat, like the Curt # C58345, either into the # 319-R7-01 at some point, or where the #...
    view full answer...
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  • Connecting Ignition Switched Power From 2015 Toyota Prius v to Enclosed Trailer
    You will need to use a circuit tester like # PTW2979 to find a wire in your 2015 Toyota Prius v that is hot only when you use your key (ignition switched power). When you do that you can simply wire in the Battery Isolation Solenoid # TR118665, which should be wired like in the accompanying diagram with 10 gauge wire # 10-1-1. I have added a link to a video review of the solenoid for you to check out.
    view full answer...
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Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Lindsey S
Edited by:
Lindsey S
Employee Cole B
Installed by:
Cole B
Employee Wilson B
Updated by:
Wilson B
Employee Kristina F
Updated by:
Kristina F
Employee Matthew E
Updated by:
Matthew E
Employee Isabelle B
Updated by:
Isabelle B
Employee Ronnie R
Written by:
Ronnie R

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