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Vehicle battery connection required
Includes fuse holder, battery connection wiring and other necessary wiring components
Includes fuse holder, battery connection wiring and other necessary wiring components
Warranty: One-Year Limited Warranty
Finish: Blank
Electrical System Type: 3W
Output Type: 4-Way Flat
Tail Light Circuits: 7.5 Amps
Turn and Brake Circuits: 7.5 Amps
Installation Time Exact (Minutes): 0
If your vehicle is not equipped with wiring for towing a trailer, CURT custom wiring is the ideal solution. A custom wiring harness -- also called a T-connector -- is a simple, plug-and-play electrical device that plugs into your automotive electric system and provides a standard, universal trailer wiring connection. This is done using two or more vehicle-specific, OEM-compatible connectors to plug into the taillight assembly, eliminating the need for cutting, splicing and soldering during installation. Custom wiring harnesses are made vehicle-specific, and while they are not available for all vehicles, they do offer one of the fastest, easiest and most secure ways to wire a vehicle for towing. This particular plug-in harness provides a 4-way flat connector socket and is designed to be a custom wiring harness to fit certain years of the Ram ProMaster 1500, 2500 and 3500 (to verify your vehicle compatibility, see application info). It comes with all necessary wiring components to establish a reliable trailer wiring connection, as well as a dust cover to keep the connector clean when not in use. You have a picture in mind of your next destination -- maybe it's the boat landing at your favorite fishing spot, maybe it's a campsite that overlooks one of nature's masterpieces, or maybe it's the next big jobsite. However, turning that picture into a reality takes more than just daydreaming. It takes a solid connection and the right amount of power. CURT custom wiring is made with some of the most sophisticated technology in the industry and is designed to install with ease, giving you a long-lasting electrical connection for your towing hitch setup.
CURT offers a variety of high-quality trailer hitches and accessories for select vehicle models. Find the perfect fit for your towing needs at TowUniverse.
CURT, a Lippert brand, offers a complete line of towing products and is the leading manufacturer of custom-fit trailer hitches. We offer the broadest selection of custom-fit hitches, and each one is designed, welded, and coated in Wisconsin.
CURT is also a leader in flat towing products, as well as 5th wheel, gooseneck, and weight distribution hitches, ball mounts, electrical components, cargo solutions, and other towing accessories.
For everything from passenger cars and vans to full-size pickups and SUVs, CURT is 'The First Name in Towing Products®.'
Experts available to answer your questions
Call 888-634-9494Rediscover "Us" Time | Tested. Proven. Safe. Towing Products
3 compatible vehicles
| Year | Make & Model | Notes |
|---|---|---|
| 2014 - 2026 | Ram ProMaster 1500 | Installation Time - |
| 2014 - 2026 | Ram ProMaster 2500 | Installation Time - |
| 2014 - 2026 | Ram ProMaster 3500 | Installation Time - |
Yes, the CURT Custom Wiring Harness, 4-Way Flat Output, Select Ram ProMaster 1500, 2500, 3500 Trailer Connector Kit (Part #BKDK56478) is designed to fit the 2014-2026 Ram ProMaster 1500.
The CURT Custom Wiring Harness, 4-Way Flat Output, Select Ram ProMaster 1500, 2500, 3500 Trailer Connector Kit (Part #BKDK56478) fits the following vehicles: 2014-2026 Ram ProMaster 1500; 2014-2026 Ram ProMaster 2500; 2014-2026 Ram ProMaster 3500. Always verify your specific year, make, and model before ordering.
The CURT Custom Wiring Harness, 4-Way Flat Output, Select Ram ProMaster 1500, 2500, 3500 Trailer Connector Kit (Part #BKDK56478) fits 2014-2026 Ram ProMaster 1500 models. The 2026 model year is the last year covered by this part number. For newer models, check for an updated version.
The CURT Custom Wiring Harness, 4-Way Flat Output, Select Ram ProMaster 1500, 2500, 3500 Trailer Connector Kit (Part #BKDK56478) Typical installation time is . Basic hand tools are typically all you need.
Part 56478 is designed for SUVs and Vans. The manual does not list specific vehicle makes, models or years. Contact Curt Manufacturing or consult a fitment database to confirm compatibility with your vehicle before purchasing.
The 56478 is a wiring converter for SUVs and Vans that integrates with the vehicle's taillight wiring system. It includes a converter box, custom wiring harness with color-coded wires (yellow for left turn, green for right turn, red for brake, brown for taillight), a power lead that connects to the vehicle battery, and a 4-flat connector for external use. The manual does not specify whether it is for trailer lighting, towing, or another application.
Yes. The converter system is designed only for 12-volt negative ground electrical systems. Do not use on any other system type.
Required tools are: ratchet, 10 mm socket, Phillips screwdriver, flathead screwdriver, panel trim removal tool, wire stripper, wire crimper, electrical tape, and cutting tool. Proper tools will improve installation quality and reduce time required.
Yes. You must disconnect the negative battery terminal before beginning installation. The battery is located under the driver-side floor panel, secured by six fasteners. Remove the floor panel to access it. Reconnect the negative battery terminal after all other installation steps are complete and before installing the fuse.
Mount the black converter box on the upper corner inside the rear cargo door frame on the driver side using the provided double-sided tape. The area should be flat and clean. Ensure the area is free of rust, dirt and paint before adhering.
Open the rear cargo doors. On the driver side, remove seven Phillips screws from the plastic cover to locate the vehicle taillight wiring harness connectors. Separate the connectors from the taillight housing, taking care not to damage the locking tabs. Insert the custom wiring harness end with the yellow wire between the separated connectors, ensuring they are fully inserted with locking tabs in place. Repeat this process on the passenger side using the custom wiring harness end with the green wire.
Route the custom wiring harness end with the green wire to the passenger side through the opening that runs up and over the rear cargo doors. This connects the passenger-side taillight connector to the converter system.
Drilling may be required for the ground wire connection. Locate a suitable grounding point near the connector, such as an existing screw with nut in the vehicle frame. If no suitable point exists, drill a 3/32" pilot hole for the provided screw. The area should be free of rust, dirt and paint. Before drilling, check for miscellaneous items that may be behind or under the surface to avoid personal injury or property damage.
Locate a suitable grounding point near the connector, such as an existing screw with nut in the vehicle frame, or drill a 3/32" pilot hole for the provided screw. The area must be free of rust, dirt and paint. Remove the nut from the existing screw or the provided screw, install the white ground wire ring terminal, and replace the nut to secure it.
Route the black power wire from the vehicle battery as follows: start at the wiring harness converter box, along the top of the driver-side cargo area and down along the frame located behind the driver seat. Continue from the cargo area along the bottom of the driver-side seat frame and route the power wire under the floor panel section to the battery. Use the provided cable ties to secure any loose wires. When passing the power wire through sheet metal, use an existing grommet, add a grommet, or use silicone to protect the wire from sharp edges. Avoid pinch points and hot or rotating components.
Remove the Phillips screws from the plastic seat belt trim panel and the trim around the driver-side seat and floor. Remove all plastic trim panels to allow routing of the power wire from the converter box to the battery. These panels are reinstalled after the power wire is routed.
Use a 10-amp fuse maximum. The battery connection must be fuse-protected with a 10-amp max fuse. Install the fuse after all other installation steps are complete. Do not exceed this rating, as exceeding the product rating can cause loss of warranty, overheating and potential fire.
Signal circuits are rated at 7.5 amps per side. Tail/running circuits are rated at 7.5 amps total. Do not exceed the product rating or the tow vehicle lamp load rating, whichever is lower.
Yellow = Left turn; Green = Right turn; Red = Brake; Brown = Taillight. The converter also includes a white ground wire and a black power wire that connects to the vehicle battery positive terminal.
Use 12-gauge wire or larger for the power connection from the converter to the vehicle battery. The manual specifies '12 GA wire or larger' for the power lead.
When in use, route the 4-flat connector to the center of the vehicle and out of the cargo area. When not in use, roll it up and store in a convenient, out-of-the-way location inside the trunk. Install the provided 4-flat dust cover to help prevent corrosion.
Disconnect the negative battery terminal before beginning installation. Do not lay tools across the positive battery terminal (typically noted with red covers or a red '+' symbol), as this can cause a ground short, resulting in sparks and/or electrical shocks. Use a ring terminal for the battery connection. Disconnect the negative battery cable before wiring the power wire to the battery.
Before drilling, check for miscellaneous items that may be behind or under the surface to avoid personal injury or property damage. This is especially important when drilling the 3/32" pilot hole for the ground wire connection.
Once installed, test for proper function by using a test light or connecting a properly wired trailer. All installation steps must be followed to ensure the product functions properly.
Perform periodic inspection of all wires and connections to ensure there is no visible damage or loose connections. No other maintenance intervals are specified in the manual.
The installation difficulty is rated as Easy. Installation difficulty levels are based on time and effort involved and may vary depending on the installer's level of expertise, condition of the vehicle, and proper tools and equipment.
Open the rear cargo doors. On each side (driver and passenger), remove seven Phillips screws from the plastic cover to locate the vehicle taillight wiring harness connectors. These covers provide access to the connectors you need to separate and integrate with the custom wiring harness.
The 56478 is designed for SUVs and Vans. Consult a fitment database or contact Curt Manufacturing to confirm compatibility with your specific vehicle make, model and year.
Yes, disconnect the negative battery terminal before starting. The battery is under the driver-side floor panel, secured by six fasteners. Reconnect it after all other steps are complete, before installing the fuse.
Drilling may be required. If no existing screw with nut is available for the ground wire connection, drill a 3/32" pilot hole. Before drilling, check for items behind or under the surface to avoid injury or damage.
Use a 10-amp fuse maximum. Install it after all other steps are complete. Do not exceed this rating to avoid loss of warranty, overheating and potential fire.
Use 12-gauge wire or larger for the power lead from the converter to the battery. Route it avoiding pinch points and hot or rotating components.
The converter is designed only for 12-volt negative ground electrical systems. Do not use on any other system type.
Perform periodic inspection of all wires and connections to ensure there is no visible damage or loose connections.
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