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Curt 56000 5th Wheel and Gooseneck Wiring Extension Harness - Universal 7-Pin Connector

CURT 56000 5th wheel and gooseneck wiring extension harness with 7-pin connector, universal trailer wiring adapter, 2.8 lbs
 
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: $134.66
Part Number: 56000
Manufacturer: Curt MFG
UPC #: 079976560009

Quantity in Stock :170

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CURT MfgPart 56000Universal FitCURT 56000 5th Wheel and Gooseneck Wiring Extension

Pulling a 5th wheel or gooseneck trailer and coming up short on wiring reach? The CURT 56000 extension harness solves the cable-length gap between your truck's bed-mounted 7-pin connector and the trailer's plug -- no splicing, no rigging, no electrical tape fixes. It routes cleanly through or along the truck bed rail and gives you the slack needed for a proper, secure connection every time you hook up.

Stop Fighting a Short Cord Every Time You Hook Up

5th wheel and gooseneck setups route wiring through the truck bed, and factory or aftermarket bed connectors often sit too close to the hitch to comfortably reach the trailer's plug without putting stress on the connector or the harness. The CURT 56000 is purpose-built to extend that reach, providing a clean, weatherproof bridge between the two ends.

Whether you're running a traditional 5th wheel king pin trailer or a gooseneck ball-style hookup, this extension keeps the electrical connection relaxed and strain-free -- which means longer connector life, fewer intermittent brake and light faults, and fewer roadside headaches.

Universal 7-Pin Design

Fits the standard 7-way RV blade connector used on virtually all modern 5th wheel and gooseneck trailers and tow vehicles.

Strain-Relief Extension

Adds length to relieve tension on the bed-mounted connector, protecting both the truck-side socket and the trailer-side plug from wear and damage.

Ready to Install

Plug-and-play design -- no cutting, no crimping, no splicing into existing wiring. Simply connect each end and route along the bed rail.

Compact and Stowable

At just 2.8 lbs and a 9 x 9 x 4 inch footprint, the extension coils neatly in the truck bed when not in use and doesn't add bulk during transit.

Why 5th Wheel and Gooseneck Wiring Needs an Extension

Unlike bumper-pull trailers where the 7-pin connector sits right at the hitch, 5th wheel and gooseneck setups mount the truck-side connector toward the front of the bed -- near the cab or along the bed rail. Depending on your truck bed length and hitch position, the trailer plug may be several feet away when the trailer is coupled. Without an extension, the harness stretches tight, which causes connector fatigue, intermittent connections, and eventual socket damage.

Plug-and-Play Convenience: The CURT 56000 uses standard 7-way RV blade connectors on both ends, so there is no compatibility guesswork. If your truck has a 7-pin round connector and your trailer has a 7-pin plug, this extension drops right in.

Compatibility and Fitment

The CURT 56000 is compatible with all standard 7-way RV blade-style connectors, which is the industry standard for 5th wheel and gooseneck trailers. This includes trailers wired for electric brakes, running lights, brake lights, turn signals, reverse lights, and a 12V auxiliary power circuit -- all seven pins of the standard RV wiring scheme.

  • Works with any truck or SUV equipped with a 7-pin round blade-style bed connector
  • Compatible with all 5th wheel trailers using standard 7-way wiring
  • Compatible with gooseneck trailers using a 7-pin flat or round blade connector
  • Works with CURT's own bed-mounted 5th wheel wiring kits as well as OEM and aftermarket truck bed connectors
Note on Gooseneck Use: Gooseneck trailers sometimes use a 4-pin or 5-pin connector depending on their brake and lighting configuration. Verify your trailer uses a full 7-pin RV blade connector before ordering. If your trailer uses a 4-flat or 5-flat connector, a different adapter may be needed.

Installation Overview

Installation is straightforward for any RV owner comfortable with basic trailer wiring tasks:

  • Locate your truck's bed-mounted 7-pin connector (typically mounted on the bed rail near the cab or on a bracket above the hitch)
  • Plug the female end of the CURT 56000 into the truck-side socket
  • Route the extension harness along the bed rail or through the bed to the hitch area
  • Plug your trailer's 7-pin connector into the male end of the extension
  • Verify all lights and brake controller communication before moving
Maintenance Tip: Apply dielectric grease to both connector ends before mating. This prevents corrosion at the blade contacts, which is the most common cause of intermittent lighting and brake faults on 5th wheel setups. Inspect connector pins at the start of each season for green oxidation or bent blades.
Routing Caution: When routing the extension through the truck bed, avoid running it across sharp bed rail edges or in contact with moving hitch components. Use zip ties or cable clamps to secure the harness so it cannot contact the hitch plate or kingpin box during travel.

Physical Specifications

ManufacturerCURT Manufacturing
Part Number56000
UPC612314560004
Weight2.8 lbs
Package Dimensions9.0" x 9.0" x 4.0"

Electrical Specifications

Connector Type7-way RV blade (standard round)
Pin Configuration7-pin: electric brake, running lights, left turn/brake, right turn/brake, ground, 12V auxiliary, reverse
Connector GenderFemale (truck side) to Male (trailer side)

Application and Fitment

Primary Application5th wheel and gooseneck trailer wiring extension
Trailer Types5th wheel, gooseneck ball hitch trailers
Truck CompatibilityAny truck with a 7-pin bed-mounted connector
Trailer CompatibilityAny trailer with a standard 7-pin RV blade plug
Installation TypePlug-and-play, no wiring modification required

Package Contents

Included1x wiring extension harness
Not IncludedMounting hardware, cable clamps, dielectric grease
Important Information
  • Verify your trailer uses a 7-way RV blade connector before purchasing -- 4-flat or 5-flat trailer wiring is NOT compatible with this extension without an additional adapter.
  • This extension is for use with standard 12V trailer lighting and brake circuits only. It is not rated for high-amperage shore power or any 120V/240V application.
  • Do not allow the extension harness to drag on the ground or contact the hitch mechanism, kingpin box, or truck bed during travel -- secure with zip ties or cable clamps.
  • Inspect connector pins for corrosion or damage before each trip. Corroded pins cause intermittent brake controller faults and lighting failures that can result in failed roadside inspections.
  • The 9.0 x 9.0 x 4.0 inch package dimensions reflect the coiled harness -- the actual deployed length will be greater. Confirm the deployed length suits your truck bed and hitch configuration before installation.


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