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Curt 56322 Custom Fit Trailer Wiring Harness - Vehicle-Specific 4-Flat Connector

CURT 56322 custom fit trailer wiring harness 4-flat connector plug-and-play vehicle-specific no-splice design
 
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Part Number: 56322
Manufacturer: Curt MFG

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CURT ManufacturingPart No. 56322No-Splice InstallCURT 56322 Custom-Fit Trailer Wiring Harness

Stop splicing into your truck or SUV's factory tail light wiring and risking blown fuses, flickering lights, or voided warranties. The CURT 56322 is a vehicle-specific, plug-and-play wiring harness that taps directly into your existing OEM connector -- delivering a clean 4-flat trailer output without cutting a single wire. Designed for a precise fit on select vehicle applications, this harness takes the guesswork out of trailer wiring and gets you on the road in under an hour.

Plug-and-Play Trailer Wiring Done Right

The CURT 56322 is part of CURT's broad T-One connector lineup -- one of the most trusted families of vehicle-specific trailer wiring harnesses in the aftermarket. Unlike universal wiring kits that require you to tap, splice, and solder into factory circuits, this harness is engineered to match the exact OEM connector locations on compatible vehicles. You unplug the factory tail light connector, plug the CURT harness in between, and route the 4-flat output to your hitch receiver. That's it.

This approach keeps your vehicle's electronics fully protected. No current is pulled directly from the factory bulbs, and no wires are permanently altered. If you sell the vehicle or remove the harness, the factory wiring is untouched.

No-Splice Design

Plugs directly into OEM tail light connectors -- zero cutting or splicing into factory wiring required.

4-Flat Output

Delivers standard 4-way flat connector: left turn/brake, right turn/brake, tail lights, and ground.

Vehicle-Specific Fit

Engineered to match exact OEM connector geometry on compatible vehicle make/model/year combinations.

Plug-and-Play Install

Most installations complete in under one hour with basic hand tools -- no wiring diagram required.

What Is a T-One Connector and Why Does It Matter?

CURT's T-One connectors (which include the 56322) use a converter module that reads your vehicle's existing tail light signals and translates them cleanly to the standard 4-flat trailer format. This is especially important on modern vehicles with LED tail lights, CAN bus electrical systems, or combined turn/brake functions -- situations where a simple splice can confuse the vehicle's body control module or trigger warning lights on the dash.

The 56322 harness includes an in-line circuit converter (also called a loop module or T-connector module) that handles this signal conversion transparently. Your trailer's turn signals, brake lights, and running lights will function exactly as expected without any dashboard warnings or electrical gremlins.

Clean OEM Integration: Because the harness plugs into existing connectors rather than tapping wires, your factory warranty coverage on the vehicle's electrical system is not compromised. The installation is fully reversible.

4-Flat Trailer Connector -- What It Supports

The 4-way flat connector output on the 56322 is the most widely used trailer connector format in North America. It supports:

  • Left turn and brake signal
  • Right turn and brake signal
  • Tail/running lights
  • Ground (common ground through the flat connector's fourth pin)

This connector format is compatible with most utility trailers, boat trailers, small enclosed cargo trailers, pop-up campers, and lightweight travel trailers. If your trailer uses a 5-flat, 6-round, or 7-way RV blade connector, you will need a separate adapter -- the 56322 itself outputs a standard 4-flat.

Trailer Connector Compatibility: The 4-flat output on this harness works with any trailer wired for 4-way flat. For trailers with electric brakes or a 12V charge line (requiring 5-way or 7-way), an additional adapter or a different harness will be needed. The 56322 does not provide a brake controller output or auxiliary power pin.

Installation Overview

CURT designs the 56322 so that a competent DIYer can complete the install in a typical driveway setting. General steps follow this pattern:

  • Open the vehicle's tailgate or lift the cargo floor to access the tail light connectors (location varies by vehicle)
  • Unplug the factory OEM connector from each tail light assembly
  • Plug the CURT harness connectors into the OEM sockets in their place
  • Plug the OEM tail light connectors into the corresponding sockets on the CURT harness
  • Route the 4-flat pigtail out to the hitch area and secure with the included clips or ties
  • Test all trailer light functions before towing
Maintenance Tip: Apply dielectric grease to the 4-flat connector pins before each towing season to prevent corrosion, especially if the connector is exposed to road spray or weather between trips. Dielectric grease does not conduct electricity -- it seals out moisture without interfering with the electrical connection.

About CURT Manufacturing

CURT is one of the largest and most comprehensive trailer hitch and towing accessory brands in North America. Their custom wiring harnesses are engineered using vehicle-specific OEM connector data and are tested against SAE J1500 trailer connector standards. The T-One connector family covers hundreds of vehicle applications from compact SUVs to full-size pickups to minivans, and CURT updates fitment data regularly as new model years are released.

Pair With Your CURT Hitch: For a complete plug-and-tow setup, the 56322 is designed to complement a CURT vehicle-specific receiver hitch on the same vehicle application. Buying both as a matched set ensures connector length and routing are correct for your hitch receiver location.

Product Specifications

ManufacturerCURT Manufacturing
Part Number56322
UPC612314563227
Product Weight1.85 lbs
Package Dimensions9.0 in x 6.0 in x 3.0 in

Electrical Specifications

Connector Output Type4-way flat (4-flat)
Functions SupportedLeft turn/brake, right turn/brake, tail/running lights, ground
Signal ConversionIn-line loop module / T-connector converter included
Brake Controller OutputNot included -- 4-flat only
Auxiliary 12V OutputNot included

Installation Details

Installation MethodPlug-and-play, no splicing or cutting
Tools RequiredBasic hand tools only (flathead screwdriver typical)
Estimated Install TimeUnder 1 hour for most applications
OEM Wiring AlterationNone -- fully reversible installation
Hardware IncludedWiring harness, in-line converter module, mounting clips/ties

Compatibility

Harness SeriesCURT T-One Custom Wiring family
Trailer Connector StandardSAE J1500 4-flat
Compatible Trailer TypesUtility, boat, cargo, pop-up camper, lightweight travel trailer
Vehicle FitmentVehicle-specific -- verify by make/model/year before ordering

Package Contents

Wiring HarnessIncluded
In-Line Converter ModuleIncluded
Mounting HardwareIncluded (clips/cable ties)
Installation InstructionsIncluded
Important Information
  • Verify fitment for your specific vehicle make, model, and year before purchasing -- this is a custom-fit harness, not a universal kit.
  • The 56322 outputs a 4-flat connector only. It does not support electric trailer brakes, a 12V charge line, or any connector format beyond 4-way flat without a separate adapter.
  • Do not exceed the trailer connector's rated current capacity. Overloading the circuit (for example, by adding aftermarket LED light bars on the trailer) can damage the converter module or vehicle wiring.
  • Confirm that your trailer plug matches the 4-flat format before connecting. Forcing mismatched connectors can bend or break pins.
  • Test all light functions -- left turn, right turn, brake, and running lights -- before every towing trip. A non-functioning trailer light is a safety hazard and a ticketable violation in all U.S. states.
  • If your vehicle dashboard shows a trailer light fault warning after installation, confirm the harness connectors are fully seated. Some vehicles require a brief ignition cycle to reset the system.


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