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2008 - 2011 BMW 135i
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Complete CURT Class 1 1-1/4" trailer hitch and 5-flat wiring kit (with 4-way to 5-way adapter for surge brakes) engineered for the 2008 - 2011 BMW 135i. Vehicle-specific hitch fit, with a universal taillight converter for trailer wiring; all hardware and instructions included.
This custom kit fits the following vehicles:
All Hardware and Installation Instructions Included!
However you define adventure -- whether it's climbing onto the back of a mountain bike, hunting from the top of a tree stand or camping with the family a long way from nowhere -- CURT class 1 hitches provide a light-duty towing receiver to help you Bring It. Each is made to fit a specific vehicle, providing easier installation, a better fit and optimal towing capacity. Custom class 1 trailer hitches are available for a variety of smaller vehicle types, including the compact car, crossover, minivan and small SUV. This particular class 1 hitch is designed to be a custom hitch for certain years of the BMW 1 Series M, 128i and 135i (to verify vehicle compatibility, see the CURT application guide at curtmfg.com). Tested in accordance with SAE J684, it offers a weight carrying capacity of 2,000 lbs. GTW and 200 lbs. TW. It is equipped with 1-1/4" receiver tube opening to accept a ball mount shank or other hitch mount. This class 1 hitch also comes with all necessary mounting hardware. With its lightweight design and smaller receiver tube size, a class 1 hitch is especially useful for adding cargo space with a hitch-mounted bike rack or cargo carrier. They can also typically be used to tow small trailers such as a utility trailer, kayak trailer or teardrop camper (never exceed the lowest weight capacity of any towing component; i.e. the vehicle, hitch, trailer, etc). Though CURT class 1 trailer hitches are only intended for light-duty towing, we apply the same principles of quality as we do to the rest of our rear mount hitches. Each class 1 hitch is made with hands-on engineering, high-strength steel and precise welding. We use a co-cured finish of liquid A-coat, inside and out, and durable black powder coat to provide a lasting defense against rust, chips and UV rays.
This CURT universal taillight converter is the go-to solution when a vehicle-specific custom harness isn't available for your make and model. It provides a standard 4-way flat trailer connector for tail lights, brake lights and turn signals, and is compatible with most vehicles (light splicing required). Built with surface-mount circuitry and a potted enclosure for durability against moisture, vibration and road debris. Includes a dust cover and is backed by a limited one-year 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 |
|---|---|---|
| 2008 - 2011 | BMW 135i | — |
Yes, part number 11184 is designed for BMW 128i Coupe and 128i Convertible models. It also fits 135i Coupe and 135i Convertible. Verify your exact model before purchase.
Curt 11184 is designed for use with ballmount #55001 or #45501.
You will need: 8, 10, and 19mm sockets; 12" extension; ratchet; 19mm wrench; flat blade screwdriver; rotary tool with cut-off wheel; and torque wrench.
No, drilling is not required. The hitch mounts to existing bumper beam mount studs on the vehicle.
All 12mm hardware must be torqued to 82 lb-ft.
The hitch has a gross load capacity of 2,000 lbs trailer weight and 200 lbs tongue weight when used as a weight-carrying hitch. Do not exceed your vehicle manufacturer's recommended towing capacity.
The kit includes the hitch receiver and mounting hardware: (4) M12x1.5 Class 10.9 hex nuts (part 20-00133) and (4) 1/2" lock washers (part 30-00153). All fasteners needed for installation are included.
Yes, Curt 11184 is designed for BMW 135i Convertible models, as well as 135i Coupe, 128i Coupe, and 128i Convertible.
Follow these steps in order: (1) Remove the two underbody panels at the rear of the vehicle. (2) Lower the exhaust by removing the 10mm bolt from the hanger bracket at the rearmost mounting point. (3) Remove the rear bumper fascia by releasing the eight bumper fascia tabs with a screwdriver and removing the four screws with an 8mm socket. (4) Raise the hitch into position over the four bumper beam mount studs and secure with 12mm hex nuts and 1/2" lock washers. (5) Torque all 12mm hardware to 82 lb-ft. (6) Trim the underbody panel to clear the hitch. (7) Raise the exhaust back into position, reinstall the 10mm exhaust hanger bolt, and reinstall the rear bumper fascia and underbody panels.
Use a flat blade screwdriver to release the eight bumper fascia tabs. Then remove the four screws securing the fascia using an 8mm socket. The fascia can then be removed to access the bumper beam mount studs.
Remove the 10mm bolt from the hanger bracket at the rearmost mounting point. This allows the exhaust to be lowered enough to provide clearance for hitch installation. After the hitch is secured and the underbody panel is trimmed, raise the exhaust back into position and reinstall the 10mm bolt.
Raise the hitch into position over the four bumper beam mount studs located between the trunk panel and the bumper beam. Do not sandwich the hitch between the bumper beam and the vehicle frame. Secure the hitch using a 12mm hex nut and a 1/2" lock washer on each of the four studs.
Yes, you must trim the underbody panel to clear the hitch. The manual shows the trimming area in the "Under Body Panel Trimming" diagram. This is a permanent modification required for proper fitment.
The hitch is secured using four M12x1.5 Class 10.9 hex nuts (part 20-00133) and four 1/2" lock washers (part 30-00153), one set on each of the four bumper beam mount studs. All fasteners are included in the kit.
The tongue weight capacity is 200 lbs when the hitch is used as a weight-carrying hitch. Do not exceed this limit or your vehicle manufacturer's recommended towing capacity.
All non-trailer loads applied to this hitch must be supported by auxiliary stabilizing straps. Failure to properly support non-trailer loads will void the product warranty.
Periodically check the receiver hitch to ensure that all fasteners are tight and that all structural components are sound. This helps maintain the integrity and safety of the installation.
Curt Manufacturing warrants this product to be free of defects in material and workmanship at the time of retail purchase by the original purchaser. If the product is found to be defective, Curt may repair or replace it at their option when returned prepaid with proof of purchase. Alteration, misuse, or improper installation voids the warranty.
Professional installation takes approximately 120 minutes. DIY installation by a novice may take up to 24 hours.
Call Curt Manufacturing Technical Support at 877-287-8634 for installation assistance.
The CURT taillight converter (56496) is a module that converts a vehicle's taillight wiring to a 4-flat trailer connector. It allows you to connect a trailer with a 4-flat plug to vehicles that do not have a factory trailer connector. The converter interprets your vehicle's existing taillight signals (brake, turn, and tail lights) and outputs them through the 4-flat connector to power the trailer lights.
The converter is designed for SUVs, mini and full-sized vans, passenger cars, and pickup trucks. The manual provides wiring location guides for three vehicle categories: SUVs/vans (S-series locations), passenger cars (P-series locations), and pickup trucks (T-series locations). However, the manual does not provide a specific year, make, or model compatibility list. Contact CURT or consult a fitment database to confirm compatibility with your specific vehicle.
The converter is designed only for 12-volt negative ground electrical systems. Before purchasing, confirm your vehicle uses a 12-volt negative ground system. If your vehicle uses a different voltage or positive ground system, this converter will not work. Check your vehicle owner's manual or contact the vehicle manufacturer to verify your system type.
Included with the converter: snap locks, double-sided tape, cable ties, ground screw, and white ground wire with ring terminal. You must source separately: 12 gauge wire (or larger), 10-amp fuse (maximum), fuse holder, butt connectors, and ring terminal. Alternatively, CURT part 55151 is a kit that includes these items. Tools needed: multimeter or test light for wiring identification, wire strippers, and a drill with 3/32" bit (if drilling a ground hole is necessary). A socket wrench or screwdriver may be needed to disconnect the battery terminal.
Yes. Step 3 of the installation instructions requires you to locate the vehicle battery and disconnect the negative battery terminal before wiring the converter. The negative terminal must remain disconnected until Step 7, after all wiring is complete and the fuse is installed. This prevents electrical shorts and damage during installation.
The manual provides a 'How to Determine Vehicle Wiring Types' procedure on page 2. With the vehicle running and all lights off, probe the taillight connectors (still connected to the vehicle) using a multimeter set to DC volts or a test light. Wires carrying less than 2 volts (or that do not illuminate a test light) are not used. Then activate each light circuit (left turn, right turn, tail, brake) one at a time and probe the remaining wires to identify which wires carry which signals. This determines whether your vehicle has a two-wire system (combined stop/turn with independent tail) or three-wire system (independent stop, turn, and tail signals). This information is essential for correctly splicing the converter wires in Step 4.
Mount the converter near the taillight. The manual provides a wiring location guide showing eight possible locations for SUVs/vans (S1–S8), seven for passenger cars (P1–P7), and five for pickup trucks (T1–T5). These locations are behind taillight housings, rear bumpers, rear access panels, or under rear floor panels, depending on vehicle type. Once you have selected the location, adhere the black converter box using the provided double-sided tape and secure it with the included cable ties. Ensure the area is clean and dry before applying the tape.
In Step 4, use snap locks to attach the converter's input wires to the corresponding vehicle harness wires. The converter has four input wires: red (brake), yellow (left turn), green (right turn), and brown (tail). The wiring installation table on page 3 shows which converter wire splices to which vehicle wire, depending on whether your vehicle has a two-wire or three-wire system. For a two-wire system: green splices to the right stop/turn wire, yellow to the left stop/turn wire, brown to the tail wire, and red is grounded. For a three-wire system: green splices to the right turn wire, red to the stop wire, yellow to the left turn wire, and brown to the tail wire. Photos A, B, and C on page 3 show how to install the snap locks.
In Step 6, locate a suitable grounding point near the taillight. The white ground wire has a ring terminal attached. If an existing screw with nut is available in the vehicle frame, attach the ring terminal to that screw. If not, drill a 3/32" pilot hole in a clean, rust-free, paint-free area of the vehicle frame and use the provided screw to secure the ring terminal. Before drilling, check for hidden items behind or under surfaces to avoid damage and personal injury.
Route 12 gauge wire (or larger) from the converter's black power wire to the vehicle battery positive (+) terminal, taking care to avoid pinch points and hot or rotating components. At the battery, use a ring terminal (not included) to attach the wire to the positive post. Install a 10-amp fuse (maximum) in a fuse holder (not included) on this power wire, positioned as close to the battery as possible. Install the fuse only after all other wiring steps are complete. The negative battery terminal must remain disconnected until the fuse is installed.
In Step 7, secure any loose wires with the provided cable ties. This prevents wires from moving, chafing, or becoming pinched during vehicle operation. Route the 4-flat connector to the center of the vehicle when in use, and secure it in a convenient out-of-the-way location when not in use.
The converter is rated for a maximum of 3.0 amps per signal circuit (left turn, right turn, brake) and 6.0 amps total for tail and running circuits. Do not exceed these ratings. Also do not exceed your tow vehicle's lamp load rating, whichever is lower. Exceeding the product rating can cause loss of warranty, overheating, and potential fire.
The battery connection must be fuse-protected with a 10-amp maximum fuse. Do not use a fuse larger than 10 amps. The fuse holder and fuse are not included and must be purchased separately, or as part of CURT part 55151 kit. Install the fuse after all other wiring steps are complete and immediately before reconnecting the negative battery terminal.
Use 12 gauge wire or larger to route from the converter's black power wire to the vehicle battery. This wire must be routed carefully to avoid pinch points and hot or rotating components. The wire is not included and must be purchased separately, or as part of CURT part 55151 kit.
The converter has four input wires: red (brake signal), yellow (left turn signal), green (right turn signal), and brown (tail/running light signal). There is also a white ground wire with a ring terminal. Each input wire is spliced to the corresponding vehicle taillight wire using snap locks, according to your vehicle's wiring type (two-wire or three-wire system). The black power wire connects to the vehicle battery positive terminal through a fused connection. The white ground wire connects to the vehicle frame or body.
Before drilling any holes, check for miscellaneous items (wires, fuel lines, brake lines) that may be hidden behind or under surfaces to avoid damage and personal injury. Disconnect the negative battery terminal before beginning any wiring work. When routing the power wire to the battery, avoid pinch points and hot or rotating components. Ensure the area where you ground the converter is free of rust, dirt, and paint. Do not exceed the converter's amperage rating (3.0 amps per signal circuit, 6.0 amps total for tail/running) or your vehicle's lamp load rating, as this can cause overheating and fire. Use a 10-amp maximum fuse on the battery connection.
The manual provides two testing methods. Method 1 (test light): Attach the ground lead of the tester to the exposed ground terminal of the 4-flat connector. Activate the tow vehicle's left turn, right turn, tail, and brake lights one at a time. Probe the three receptacles of the 4-flat to confirm proper functionality. Method 2 (trailer): Mate the 4-flat with a trailer and run the same test using the trailer lights. If a function on the trailer lights does not work, disconnect the trailer 4-flat, turn the vehicle functions off, and recheck with a circuit tester. If the circuit tester shows the function is good, the problem is with the trailer, not the converter.
Included: snap locks, double-sided tape, cable ties, ground screw, and white ground wire with ring terminal. Not included: 12 gauge wire, 10-amp fuse, fuse holder, butt connectors, and ring terminal for the battery connection. These items must be purchased separately or as part of CURT part 55151 kit, which is sold separately.
After securing all loose wires with cable ties and installing the fuse on the battery power wire, reinstall all items you removed during installation (trim panels, bumpers, etc.). Reconnect the negative battery terminal. When the converter is in use, route the 4-flat connector to the center of the vehicle. When not in use, secure the connector in a convenient out-of-the-way location to prevent damage.
The converter fits SUVs, vans, passenger cars, and pickup trucks with 12-volt negative ground systems. The manual does not provide a specific year/make/model list. Contact CURT or check a fitment database with your vehicle details to confirm compatibility.
You must source: 12 gauge wire, 10-amp fuse, fuse holder, butt connectors, and a ring terminal for the battery. These are available separately or as CURT part 55151 kit.
Yes. Disconnect the negative battery terminal in Step 3 before wiring, and keep it disconnected until the fuse is installed in Step 7.
Drilling may be required. If a suitable existing screw is not available near the taillight for grounding, you must drill a 3/32" pilot hole in the vehicle frame. Before drilling, check for hidden items (wires, fuel lines) behind or under surfaces to avoid damage.
Maximum 3.0 amps per signal circuit and 6.0 amps total for tail/running circuits. Do not exceed these ratings or your vehicle's lamp load rating, whichever is lower.
Before drilling, check for hidden items (wires, fuel lines, brake lines) behind or under surfaces to avoid damage and personal injury.
Disconnect the trailer 4-flat connector from the converter. Turn off the corresponding function on the vehicle (e.g., turn off the left turn signal if the left turn on the trailer is not working). Recheck the function using a circuit tester on the 4-flat receptacles. If the circuit tester shows the function is working properly, the problem is with the trailer, not the converter. If the circuit tester shows the function is not working, the converter or vehicle wiring connection may be faulty.
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