Ask a Question About This Product
Our in-house experts typically reply within one business day.
Our in-house experts typically reply within one business day.
CURT
Verify Fitment
Select your vehicle to confirm this part fits.
2014 - 2017 BMW BMW
Confirmed to Fit
Always the correct part
We know our products
Quality Products
Free Shipping!
Always the correct part
We know our products
Quality Products
Free Shipping!
| Battery-Powered | Yes |
| Converter Type | PWM (Stop/Tail) |
| Electrical System Type | PWM |
| Finish | N/A |
| Material | Blank |
| Mount Type Description | Blank |
| Output Type | 4-Way Flat |
| Side Application Type Description | Blank |
| T-Connector Location | S4 |
| Tail Light Circuits | 7.5 Amps |
| Turn and Brake Circuits | 5.0 Amps |
| Warranty | One-Year Limited Warranty |
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 888-634-94941 compatible vehicles
| Year | Make & Model | Notes |
|---|---|---|
| 2014 - 2017 | BMW BMW | — |
The 14-17 BMW BMW CURT 4-flat Plug and Play Trailer Wiring (Part #CTW75) fits 2014-2017 BMW BMW models. The 2017 model year is the last year covered by this part number. For newer models, check for an updated version.
The 14-17 BMW BMW CURT 4-flat Plug and Play Trailer Wiring (Part #CTW75) fits the following vehicles: 2014-2017 BMW BMW. Always verify your specific year, make, and model before ordering.
Yes, the 14-17 BMW BMW CURT 4-flat Plug and Play Trailer Wiring (Part #CTW75) is designed to fit the 2014-2017 BMW BMW.
The 14-17 BMW BMW CURT 4-flat Plug and Play Trailer Wiring (Part #CTW75) Refer to the included instructions for installation details. Basic hand tools are typically all you need.
The CURT 56404 is a custom trailer light harness designed for SUVs and Vans with rear lift gates. It integrates with the vehicle's factory taillight system to provide trailer lighting control. The harness connects to the vehicle's electrical system and outputs a 4-flat trailer connector. It requires a powered converter module to function and must be used on 12-volt negative ground systems only.
The CURT 56404 is designed for SUVs and Vans with rear lift gates. The harness uses wiring locations S9 and S10, which are behind the driver and passenger side rear access panels. Verify your vehicle has these access panels and a rear lift gate. The system requires a 12-volt negative ground electrical system. Consult your vehicle owner's manual or the vehicle manufacturer to confirm compatibility with your specific make and model.
The CURT 56404 must be used only on 12-volt negative ground electrical systems. The converter system is designed specifically for this configuration and will not function on positive ground or other voltage systems.
Required tools are: ratchet, cutting tool, socket extension, wire crimper, Torx bits (T-20 and T-15), wire stripper, panel trim removal tool, electrical tape, and flathead screwdriver. Proper tools will improve installation quality and reduce installation time.
The manual shows a Hardware Photo on page 1 but does not itemize the contents. Based on the instructions, the kit includes: a custom wiring harness with yellow, green, and black wires; a powered converter module; a 4-flat connector; cable ties; a 4-flat dust cover; a fuse holder with 15-amp fuse; double-sided tape for converter mounting; a ring terminal for ground connection; and a screw for ground attachment. Verify the contents of your kit match the Hardware Photo.
Yes. The negative battery terminal must be disconnected before beginning installation. In Step 2, lift the floor panel and disconnect the negative battery terminal. Be sure to fasten this wire down and away from the battery when completing the installation. The negative battery cable must also be disconnected before wiring the power wire to the converter.
In Step 1, open the rear lift gate and remove: all trunk floor coverings, the trunk storage tray, the sub-woofer housing (disconnect it first), and the spare tire (loosen the tie-down first). Set these items aside. Additional panels and trim will be removed during subsequent steps, but these are the initial removals required to access the battery and wiring routes.
In Step 10, open the battery compartment and locate a spot to mount the converter close enough to connect the power and ground wires. The converter is mounted using the provided double-sided tape. Do not connect the power and ground wires at this point; complete all other installation steps first.
Follow these steps in order: (1) Remove trunk items and disconnect battery; (2) Remove rear scuff panel and disconnect latch sensor; (3) Remove taillight access panels and fasteners; (4) Remove rear hatch trim and disconnect lift gate light and hatch close connectors; (5) Remove driver-side trim cover and access panel; (6) Remove weather stripping and side wall trim; (7) Mount converter near battery; (8) Route custom wiring harness from floor through side panels to lift gate hinge and to taillight connectors; (9) Connect custom wiring to driver-side taillight with yellow wire between factory harness; (10) Connect custom wiring with green wire to passenger-side taillight; (11) Reinstall all panels and connectors; (12) Route black power wire from battery to converter; (13) Connect ground wire; (14) Install fuse and test; (15) Reconnect negative battery terminal.
In Step 12, disconnect the driver-side factory wiring and install the custom wiring end with the yellow wire in between the factory harness. Separate the connectors from the taillight housing carefully to avoid damaging the locking tabs. In Step 13, route the custom wiring with the green wire to the passenger-side taillight connectors and repeat the same process. The factory connectors remain in place; the custom harness wires are inserted between the factory harness and the taillight.
In Step 11, route the custom wiring ends along the floor to the driver-side access panel and up the side wall behind the vehicle side trim panels, along the removed weather stripping to the lift gate hinge. Then route the custom wiring along the lift gate hinge and out under the removed lift gate trim panel to the driver-side taillight connectors. Use the provided cable ties to secure any loose wires while routing. When not in use, the 4-flat connector should be rolled up and stored in a convenient, out-of-the-way location inside the trunk.
The custom wiring harness contains the following signal wires: Yellow = Left turn signal; Green = Right turn signal; Red = Brake signal; Brown = Taillight (running lights). The harness also includes a black power wire that connects to the vehicle battery positive terminal and a white ground wire that connects to the vehicle body. These colors match standard trailer lighting conventions.
Route the black 12 GA power wire from the converter to the vehicle battery location, taking care to avoid pinch points and hot or rotating components. 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. Connect the black wire to the positive battery terminal using a ring terminal. Secure the power wire to the vehicle chassis using the provided cable ties. Install the fuse holder with a 15-amp fuse after all other steps are complete. The battery connection must be fuse-protected with a 15-amp maximum.
Attach the ring terminal of the white ground wire to the vehicle body using the screw provided. If necessary, drill a 3/32-inch hole to mount the ground connection. Ensure the ground connection is secure and makes good contact with the vehicle body.
The battery connection must be fuse-protected with a 15-amp maximum fuse. The fuse holder with a 15-amp fuse is provided. Install the fuse after all other installation steps are complete. Exceeding the 15-amp rating can cause loss of warranty, overheating, and potential fire.
Signal circuits (left turn, right turn, brake): 5.0 amps per side. Tail/Running circuits (taillight): 7.5 amps total. Do not exceed the product rating or the tow vehicle lamp load rating, whichever is lower. Exceeding the product rating can cause loss of warranty, overheating, and potential fire.
If necessary, drill a 3/32-inch hole to mount the ground wire ring terminal to the vehicle body. Use the screw provided to secure the connection.
The harness will not function until all connectors and panels are reinstalled and the vehicle hatch is closed. The vehicle will not have functionality of taillights when the hatch is open. The hatch must be closed for trailer lights to function correctly. If the connectors and panels are not replaced, the taillight will not function and an error message will be shown on the vehicle dash display.
Route the 12 GA power wire to the vehicle battery location, taking care to avoid pinch points and hot or rotating components. 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. Secure the power wire to the vehicle chassis using the provided cable ties. Before drilling any holes, check for miscellaneous items that may be behind or under any surface to avoid personal injury or property damage.
Once the 12-volt power wire is connected to the harness, verify that the harness is functioning by attaching the battery and testing with a test light, 4-flat tester, or a functioning trailer. Ensure all panels are reinstalled, all connectors are plugged in, and the hatch is closed before testing. If the harness does not function, check that all connections are secure and the fuse is properly installed.
When not in use, roll up the 4-flat connector and store it in a convenient, out-of-the-way location inside the trunk. Install the provided 4-flat dust cover to help prevent corrosion. Secure any loose wires with the provided cable ties.
Periodic inspection of all wires and connections should be performed to ensure there is no visible damage or loose connections. Check the harness, converter, power wire, ground connection, and all panel connections regularly. Tighten any loose connections and replace damaged wires or connectors immediately.
The manual rates the installation difficulty as Moderate. The installation involves removing multiple interior trim panels, routing wiring through the vehicle, making electrical connections, and drilling a hole for the ground wire. While the manual provides detailed step-by-step instructions, the complexity and the need for proper tools suggest that professional installation may be beneficial. Consult with a qualified installer if you are unsure about any step.
The CURT 56404 is designed for SUVs and vans with rear lift gates and uses wiring locations S9 and S10 (behind driver and passenger rear access panels). Verify your vehicle has these access panels and a 12-volt negative ground electrical system. Contact CURT or your vehicle manufacturer to confirm fitment for your specific make and model.
Yes. Disconnect the negative battery terminal before beginning installation. The negative battery cable must also be disconnected before wiring the power wire to the converter. Reconnect it after all other installation steps are complete.
The battery connection must be fuse-protected with a 15-amp maximum fuse. Install the fuse after all other installation steps are complete. Exceeding 15 amps can cause loss of warranty, overheating, and potential fire.
Drilling may be required. You will need to drill a 3/32-inch hole for the ground wire connection to the vehicle body if an existing hole is not available. No other drilling is specified in the installation steps.
No. The harness will not function until all panels are reinstalled and the vehicle hatch is closed. The hatch must be closed for trailer lights to function correctly. If panels are not replaced, the taillight will not function and an error message will appear on the vehicle dash display.
First, verify that all connectors and panels are reinstalled and the vehicle hatch is closed. The harness will not function if the hatch is open or if panels are not replaced. Check that the negative battery terminal is reconnected. Verify that the 12-volt power wire is connected to the converter and the positive battery terminal with a ring terminal. Confirm that the fuse holder with a 15-amp fuse is properly installed. Test the harness with a test light, 4-flat tester, or functioning trailer. If the harness still does not function, check that all wiring connections are secure and that the yellow wire is properly inserted between the factory harness at the driver-side taillight and the green wire is properly connected at the passenger-side taillight.
An error message on the vehicle dash display indicates that the connectors and panels have not been properly reinstalled. Verify that all removed panels are reinstalled, all connectors (including the latch sensor and lift gate light connectors) are plugged in, and the vehicle hatch is closed. The harness will not function until all connectors and panels are reinstalled and the hatch is closed. If the error persists after reinstalling all panels and connectors, check that the custom wiring is properly connected to the factory taillight harness.
Yes, this is normal and expected behavior. The harness will not function when the hatch is open. The vehicle will not have functionality of taillights when the hatch is open. The hatch must be closed for trailer lights to function correctly. This is by design to prevent electrical issues when the hatch is open.
On Sale Today
Original price was $150.90. Current price is $135.58.You save $15.32 (10%)
Free Shipping
Ships free on all orders
Authorized Dealer
Quick Ship
In stock and ready to ship — order now!
FREE ShippingFREE SHIPPING
Estimated delivery Sat, Aug 15 - Tue, Aug 18
Order before 2 PM EST Monday–Friday for same-day processing
Guaranteed safe & secure checkout
Total for 2 items:
$494.57$618.70
No reviews have been added for this product.
