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Install a 4-way trailer connector on your vehicle without cutting or splicing into your wiring. Zero-contact interface sensors identify the current flowing through each wire by simply clamping onto it. Circuit-protected module is made using SMT.
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This revolutionary wiring method makes it fast, easy, and safe to add a 4-way connector to your vehicle so you can power your trailer's lights. Unlike traditional tail light wiring harnesses, which either splice into your vehicle's wiring or plug into designated ports in your factory harness, this system bypasses your vehicle's wiring entirely. Just clamp the intuitive sensors onto the individual wires of your OEM tail light harness and let the ZCI system do the rest.
Zero-Contact Interface Sensors
Each zero-contact interface (ZCI) sensor included with this harness is able to read the current that travels through the wire it is clamped onto. Upon sensing the specific modulation of that wire, a signal can be sent along the wire that connects the sensor to the included 4-way flat trailer connector. That signal is then transmitted through the connector to activate the appropriate function on your trailer lights.
Universal, Worry-Free Design
No Splicing, Cutting, or Connecting to Factory Wiring
Because the ZCI sensors can read the signals sent through your vehicle's wires just by clamping onto them, no cutting or splicing is necessary. The system completely bypasses all of your vehicle's wiring. As a result, your trailer's lights will be powered without overloading your vehicle's electrical system. And there is no chance of damaging feedback either.
When using this ZCI harness, you don't have to worry about voiding your warranty, nor do you need to be concerned about any potentially damaging errors on your part if you're not an experienced do-it-yourselfer. And if you have a vehicle that doesn't allow certain modifications - like a leased car or truck - you can install this harness and remove it later with no obvious alteration to the vehicle.
Maximum Compatibility
This wiring harness is universal. You can use it on any vehicle that operates on a 12V, negative ground system. Because installation is so simple, you can easily remove the unit and transfer it to another car or truck at any time.
In addition, the ZCI sensors are able to read the signals sent by multiplex wiring systems and systems with pulse width modulation (PWM) and low-side-switched wiring, making the harness compatible with nearly all automotive wiring systems. This unit also works with both standard incandescent tail light bulbs and LED bulbs.
Built-In Tail Light Converter
Most trailers run on a 2-wire system - wherein the brake and turn signals are carried on a single wire. Many vehicles, however, are built with separate brake and turn signals. This type of system is referred to as a 3-wire system. If your vehicle operates on a 3-wire system, it will need to be converted so that it will be compatible with the wiring system of your trailer. This is done by adding a tail light converter to your wiring setup to combine the brake and turn signal functions of your automobile so that they run on a single wire to properly activate your trailer's tail lights.
This ZCI unit has a tail light converter built in to ensure proper functioning with any vehicle that operates on a 3-wire system. If your car has a 2-wire system and therefore does not need a converter, don't worry. The method of installing the sensors will take into account the wiring configuration of your vehicle so that only the necessary sensors are used, making sure the appropriate signals are sent back to the 4-way.
Installation
This universal harness connects to your vehicle's tail light wiring harness. To connect, just follow the included instructions. There are 4 ZCI sensors included. Each sensor has a colored label on it. Depending on your application, you will need to connect all or some of these sensors to the factory wires indicated in the instructions.
To get the power necessary to operate, the harness must be connected to a 12V power source. The included installation kit provides the hot lead required to connect this module to your car battery. When all connections have been made, connect the hot lead to the black wire on the ZCI power module and run the other end of the lead up to your car battery. Connect the hot lead to the included fuse holder, and then connect the fuse holder to the positive terminal on your battery. Then insert the included 15-amp fuse into the fuse holder.
Once installation is complete, the 4-way connector will be stowed in an out-of-the-way location either within your cargo area or beneath your vehicle, near the trailer hitch. If you choose to mount the connector near your hitch, a mounting bracket (sold separately) is recommended to keep the connector secure.
It is also recommended that you use a small amount of grease on all electrical connections on the 4-pole connector to help prevent corrosion.
Surface Mount Technology
Each ZCI wiring harness is built using surface-mount technology (SMT). This method of construction involves soldering electronic components directly to the surface of a printed circuit board. SMT eliminates the need for leads, which are used in older through-hole technology. The result is a circuit board that is smaller yet provides more routing area and that offers superior performance, reliability, and durability.
Circuit boards constructed using SMT have been shown to perform better under rough conditions with excessive vibration than those made using the through-hole method. And where would vibration be more likely to occur than in towing applications? SMT components also produce less heat, leading to increased durability and longer life. In addition, lower levels of resistance ensure better performance, especially for parts that operate at higher frequencies.
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Average Customer Rating: 4.6 out of 5 stars (414 Customer Reviews)
Install a 4-way trailer connector on your vehicle without cutting or splicing into your wiring. Zero-contact interface sensors identify the current flowing through each wire by simply clamping onto it. Circuit-protected module is made using SMT.I purchased this kit for my 2018 Macan S. The battery is located at the back which makes it easy to connect to the power.
1. remove the side panels to get to the rear lights (they are snap on)
2. remove the spare wheels cover.
3. Unclips the back light connectors (left and right) and remove tape to access the wires
4. with the provided probe, check for left, right signal wires and mark them
5. with the provided probe, check for Brake and Tail light wires and mark them
6. connect the provides sensors to the corresponding wires (arrow pointing to the lightbulb).
7. Make sure to connect Ground wire (white) to the good location on the vehicle. (on the Macan it took me a while to find good connection spot due to the exceptional paint job the Porsche does, you may connected it to the battery to test it)
8. Connect the power wire to the battery, fuse should be removed.
9. run the learning mode as per interactions provided
10. I purchased a 4-pin test connector to help me with testing and troubleshot.
11. tuck in all the wires and, cover the sensors and places back to vehicle covers .
This unit works very well, it was easy to install. making sure you have a good ground spot is very important.
I used it on a 2017 Chevy bolt (think Chevy discurages people from installing a trailer hitch) since it did not come with any trailer hook up instructions. I think it gave my instaler a work out since he never did one before, but despite the cost I think it was the right way to go instead off cutting into wires etc. I dont use a trailer that much, but it has worked absolutely fine. Only problem has been that I think installer disturbed a wire hook up to a parking light (that is only needed-if lift gate is open) so he has not gotten around fixing that since he has to get into the trunk inards to do it.
Jorgen - 03/13/2023Horrible packaging, this appears to be a return that was simply re-shipped to me. Several areas of the hitch were damaged due to banging up against each other in the box. The box was not stapled, and the parts were not secure within. Although structurally no a problem the areas that are damaged down to bare metal will rust.
Jenny N - 03/25/2023The first three wiring harness that i got did not work with my 2020 ecosport the the company was not aware of the problem they were wonderful in helping me correct the issue with a different style harness. I will shop with them again.
Jim - 07/15/2023Product worked exactly as advertised. Was pleased with the installation instructions and the overall quality. The wiring was simple yet it took quite a while to integrate into my Audi Q7. It all worked and runs my double-axle boat trailer lights perfectly.
The wiring worked well on my Audi Q5.
The online video was a great help.
This unit needed to be programmed, it was not difficult. The issue is it loses it's marbles. every time I leave it hooked up, unattended, like for a fuel stop, when I come back out the parking lights are on , on the trailer only, or the brake lights are on, trailer only. the car is shut off and keys are out of it when it happens. Every time this happens you have to "re learn it". It was difficult to install on my car and I only use it once per year to tow with for vacation so I decided to live with it.
The trailer hitch is great and went on easily. The trailer light harness doesn't work very well with Mercedes because the wires are incredibly thin and rattle around in the pickups. I did a lot of research on this and what etrailer sells is probably the best option even though it isn't optimal. All and all, a satisfied customer.
The trailer hitch and wiring assembly have worked flawlessly. After calling several local installation outfits and receiving estimates of $2,000+ I decided to install myself. I have a little mechanical experience but this was the first hitch and wiring harness for me. This is my wife's X5 so I was a little nervous about popping rivets and pulling the rear bumper cover off, but eTrailer has excellent step by step video instructions by model year. The order included replacement rivets and detailed instructions. They could not have made this any easier. I really took my time and completed the job in about 5 hours. The final install looks professional and clean. The no-splice wiring harness is amazing - worth every penny.
Tools: I was able to easily pop off the existing plastics rivets, and installed the new rivets (included from eTrailer) with pliers pretty easily - you may want to borrow a plastic rivet gun from your local hardware or auto parts store. On the X5 your have to cut a small notch out of the underside of the bumper cover. I happen to have a Dremmel which worked well. You may be able to use a razor blade. The plastic is not that thick.
Pictures are attached.
Thanks etrailer!
2012 VW GTI (autobahn edition) Installation (DSG)
I had some small issues and hiccups along the way, so in order help out since I couldn't seem to find vehicle specific help, here is what I did. I did buy the CURT 4-way flat connector tester (Item #126) first to make my life easier when testing. It helps. Buy it.
First - start by removing the cargo floor carpet and pulling down the drivers side wall carpet. I did find it necessary to take the moulding trim off the top portion of where the hatch cover locks in, along with the rear seat belt guide trim so I could run the wires to the battery cleanly. There is a few star bolts holding the trim alongside the rear seats when folded down, so just do a search if can’t find it (one cover has to be popped off)
Second - Wiring. This was a little bit of a guess, as I have 3 wires, and my meter didn’t seem to be helpful since they were so small and close together. Here’s what works (drivers side):
- “Stop” module clips over the black/red wire
- Middle brown wire isn’t used
- “Left” turn signal module clips over the green/black wire
- Passenger side right turn signal clips over the green/black wire
- I screwed the ground right into a side structure panel
Running the battery cable was the bigger time suck.
- Stated above I had the drivers side rear panel trim and carpet removed, and I continued removing the front/rear drivers floor sill trim. I ran the black wire along the current loom and tucked it under the floor carpet.
- I then ran it behind the hood latch and towards the top of the metal foot rest, keeping it behind the carpet
- This is where you get to the firewall. There is a piece of foam. Remove it. Now you’ll see a rubber grommet where the clutch pedal would go through if you have a standard. I took that out, drilled a small hole to run the wire through that I attached the wire to a metal hanger to fish up and to the right of the battery box. Fish it up, grab it, and pull it through.
- Slide the grommet back into place (your wire would have been already through it) and snap it on.
- Make your connection to the battery and follow initiation instructions.
Works but for the unit’s sensitivity to perceived power to Tesla’s LED’s has the unit falsing to ‘on’ with its run light. That’s just OK of course. The latest (2023) change (Tesla moving to 16V Li-ion battery as standard) will be a good test for this Tekonsha product. ie any replacement of the cars’ 12V lead/acid battery will be 16V Lithium ion now. Please keep abreast of advances. Thank you.
This product worked as expected. The more useful information to readers may be that I installed this on a 2013 Audi Q5. I tapped into the wires and power source in the passenger rear panel. Most installation information including the video here on etrailer tell you to tap the wires in the rear hatch. This is a sloppy difficult way to do it and unnecessary. Good luck.
Excellent setup, installed on my 2019 tesla model 3, and I have had zero issues.
I have ordered a few items over the years from Etrailer and they are still functioning flawlessly today. Customer for life. Thanks again Etrailer
This product is difficult to install on modern thin gauge wiring.
Once installed it produces unreliable and erratic lighting patterns
I suggest you find an alternative product for your wiring harness needs
Jenny N - 09/08/2023The theory is great, so I ordered and installed it. BUT, it would never operate correctly. The running lights would not turn off - but all the lights worked otherwise. Even disconnected from the trailer, it would run the car battery down over a few days. etrailer tech told me that the led lights stayed on for some time due to low current draw. BUT these stayed on forever. The "Factory" customer service said that it sounded like a problem with the computer. Rather than fight the inevitable testing they needed to get a replacement, I tossed this unit and bought the "T connector" system. It installed quickly and worked correctly instantly. My recommendation is to buy the cheaper, more reliable unit.
Brooke M - 10/26/2022Well, maybe it was my vehicle (Q5), but doing this electrical installation was more difficult/annoying that installing the which was rated a 10 out of 10 for difficulty.
This is an excellent kit - bought it for my '17 Chevy Bolt, and installation went without any problems. Just make sure you do things accurately and to best quality. The kit's only as good as your installation.
Rob B - 12/07/2022The harness was easy to install with great instructions. I plan on ordering from etrailer.com for my future needs. Thanks.
It’s nice that no wires are cut to install… however the trailer lights work intermittently. When my car is off, the trailer lights stay on… I wouldn’t buy this again.
Jenny N - 12/07/2022Seems like a great idea that I don't have to cut wires or buy the expensive factory plug in trailer adapter. In practice the lights turn on and off intermittently weather I have lights on or not. Possibly the insulation is inadequate.
Jenny N - 10/10/2022This kit works perfectly! A reasonably straightforward installation, though not for a DYI'er who is uncomfortable ripping into the trim and lighting wiring harness of their vehicle. A reasonably accurate wiring diagram is very helpful, but not necessary because trial and error works well with Hall sensors used in this kit (i.e. no cutting and splicing wire is required).
Once installed, the trailer lighting load is easily handled by the power module without feedback to the vehicle lighting control circuit, although my setup does not interface with a trailer brake controller so I cannot judge full performance.
One hint - do not loose the heavy stock reference card that reminds one of the programming routine, While performing other electrical work on my car needing battery disconnection, I can never remember the programming sequence for the trailer lighting controller. Not to worry, though, the product support site has the info.
Installed on 2018 Jeep Grand Cherokee Limited with no tow package. Install was kind of a P.I.T.A. But worth doing on your own to avoid the stealership. Not too much electrical knowhow required, as the black wire on Jeep tail lights are all ground. Running the power cable was the most difficult part, and required removing the interior rear quarter panel, which I managed to break a plastic clip. Would not recommend this on a Jeep, as there is no simple way to install this on the interior of the vehicle since the tail lights are wired 100% outside of the car. I’d say skip if you are looking into this for a Jeep, and wait for an OEM trailer harness to come out from mopar.
I ordered a wiring harness but was not informed that it was out of stock . After 2 weeks I cancelled the order and had to re-order a different more costly item as I needed it quickly . Apart from that the new item arrived ok and I was pleased with the quick service .
This product fit the needs for my vehicle's requirements and application! I'is perfect for attaching my small trailer behind my Tesla.
The Tekonsha wiring harness was a bit difficult to install, as the clip-on connections are a somewhat bulky to fit in my Tesla Model 3's tight spaces. The good news is: they work as promised like a charm with our tiny camp trailer's lights. In truth, I have only had to use them once, but cannot imagine that any unforeseen problems would occur with them in the future.
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