CURT Electrical Adapter (4-Way Flat Vehicle to 7-Way RV Blade Trailer) Trailer Wiring Adapter ConnectorCURT$32.99In Stock
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Some manual wiring required
Warranty: One-Year Limited Warranty
Installation Time Exact (Minutes): 0
There are several different types of connectors used to supply power from a tow vehicle's electrical system to a trailer's wiring system. Some trailers only need the bare essentials -- running lights, brake lights and turn signals -- while others require a connection for reverse lights, electric brakes and auxiliary power. With connectors ranging from simple to complex, it may be the case that the connection between your vehicle and your trailer is not a perfect match. For example, your truck may be equipped with a 6-way round socket, but your trailer may have a 4-way flat plug. For this very common problem, CURT offers a quick and simple solution in the form of an electrical adapter. An adapter is an electrical device that allows a connection to be made between a mismatched trailer plug and vehicle socket. It easily plugs in your vehicle's electrical socket and usually requires no additional wiring. CURT offers an array of adapters to accommodate most types of plugs and sockets, including 4-way flat, 4-way round, 5-way flat, 6-way round, 7-way RV blades and more. This electrical adapter is designed to adapt a 4-way flat vehicle socket to fit a 7-way RV blade trailer plug. It features strong diecast metal construction and comes with a mounting bracket for a secure installation. This adapter does require some splicing. All CURT wiring and electrical products come with a one-year limited warranty to give you the assurance you need to tow with confidence.
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®.'
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The Curt 57185 is a combination harness that converts a vehicle's 4-way flat trailer connector into a 7-way RV blade connector with a mounting bracket. It allows you to connect trailers with 7-way RV blade connectors to vehicles equipped with 4-way flat connectors.
Yes. The 57185 requires your vehicle to be equipped with a 4-way flat trailer connector. If your vehicle does not have one, you will need to install a custom wiring harness or separate 4-way flat trailer connector before installing the 57185.
Both convert a 4-way flat connector to a 7-way RV blade connector (57185) or 6-way round connector (57183). The key difference is that 57185 includes a mounting bracket, while 57183 does not.
Single output adapters (such as 57185 and 57183) convert the 4-way flat to one trailer connector type. Dual output adapters (such as 57604, 57624, 57672, 57674, 57102) provide two connector outputs—a 4-way flat and either a 6-way round or 7-way RV blade—allowing you to use either connector type.
You will need: a 1/8" drill bit, drill, Phillips screwdriver, wire stripper, cutting tool, terminal crimpers, and a test light. The manual also lists three self-tapping screws #10 - 1/2" as required, though these are noted as not included.
No. Three self-tapping screws #10 - 1/2" are required but not included with the product. You will need to obtain these separately.
Mount the combination harness on your vehicle's bumper or other suitable surface. The mounting bracket should be positioned so the connectors are within reach of the trailer's wiring harness and near the center of the vehicle.
No. Never attach the mounting bracket directly to the hitch by cutting, welding or drilling into the hitch. Use the vehicle's bumper or other suitable surface instead.
Yes. You must drill two 1/8" holes: one for the mounting bracket and one for the ground wire connection. Before drilling, check carefully for brake lines, fuel lines, wiring and other components that could be damaged.
You need a 1/8" drill bit. This size is used for both the mounting bracket holes and the ground wire attachment hole.
Use 12 gauge (minimum) wire for all connections. Connect the wires using butt connectors to the appropriate functions: yellow for auxiliary or back-up lights, blue for electric brakes, and black for positive power with an appropriate inline fuse.
Yellow wire connects to auxiliary or back-up lights. Blue wire connects to electric brakes. Black wire connects to positive power (+) and must include an appropriate inline fuse. White wire is the ground (-) connection.
Proper grounding is required for the harness to work properly. The white wire must be attached with a ring terminal to a clean, drilled 1/8" hole using a #10 - 1/2" self-tapping screw. The vehicle's 4-way flat connector white wire cannot support the ground (-) functions of the combination harness's 4-way flat and 6- or 7-way connectors. Failing to properly ground the product can cause loss of warranty, overheating and potential fire.
Determine a suitable grounding point within reach of the combination harness. The area must be clean of dirt, debris and undercoating. Drill a 1/8" hole and attach the white wire with the ring terminal using a #10 - 1/2" self-tapping screw.
Yes. The black wire connects to positive power (+) and must include an appropriate inline fuse.
Do not exceed the product rating or tow vehicle lamp load rating, whichever is lower. Additionally, failing to properly ground the product can cause loss of warranty, overheating and potential fire.
Before drilling, be sure of what is behind the surface you are going to drill. Check for brake lines, fuel lines, wiring or any other components that may harm the vehicle's operation. Failure to check can cause damage and personal injury.
Confirm proper function with a test light or by using a properly functioning trailer. This verifies that all connections are working correctly before using the adapter.
Secure any loose wires using cable ties or equivalent product to prevent them from moving or becoming damaged.
The 57185 fits vehicles with a 4-way flat trailer connector. If your vehicle doesn't have one, you'll need to install a custom wiring harness or separate 4-way flat connector first.
You need three self-tapping screws #10 - 1/2", 12 gauge minimum wire, butt connectors, and an appropriate inline fuse for the black power wire. The mounting bracket is included.
Yes. You must drill two 1/8" holes—one for the mounting bracket and one for the ground wire. Check for brake lines, fuel lines and wiring before drilling.
Use 12 gauge minimum wire. Yellow connects to back-up lights, blue to electric brakes, black to positive power with inline fuse, and white to ground.
Properly ground the white wire to a clean, drilled surface. Failing to do so can cause loss of warranty, overheating and potential fire.
No. Never attach the bracket directly to the hitch by cutting, welding or drilling. Mount it on the bumper or other suitable surface instead.
| Part # | From Vehicle | To Trailer | Notes | Material |
|---|---|---|---|---|
| Single Output | ||||
| 57184 | 4-way flat | 7-way RV blade | See mounting brackets on pages 127 and 128 | Plastic |
| 57183 | 4-way flat | 6-way round | See mounting brackets on pages 127 and 128 | Die-cast |
| 57185 | 4-way flat | 7-way RV blade | Includes mounting bracket | Steel |
| 57186 | 4-way flat | 7-way RV blade | Includes wiring and components to splice in a brake controller connection | Plastic |
| 57506 | 4-way flat | 7-way RV blade | Ideal for towing a boat trailer with surge brakes | Plastic |
| 57626 | 4-way flat | 6-way round | Integrated test lamps display proper connections | Plastic |
| 57676 | 4-way flat | 7-way RV blade | Integrated test lamps display proper connections | Plastic |
| 56476 | 4-way flat | USCAR socket | Pair with #57015 for 4-way and 7-way RV blade output. See page 112 | Plastic |
| Dual Output | ||||
| 57604 | 4-way flat | 4-way flat | -- | Plastic |
| 57624 | 4-way flat | 6-way round | Integrated test lamps display proper connections | Plastic |
| 57627 | 4-way flat | 6-way round | -- | Plastic |
| 57674 | 4-way flat | 7-way RV blade | Integrated test lamps display proper connections | Plastic |
| 57102 | 4-way flat | 7-way RV blade | Audible back-up alarm when vehicle in reverse (97 decibels) | Plastic |
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