ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit

Very well thought out product, no cutting or drilling required to install. The light kit is superb as well, loved the way it attaches to the wires and operates independently of the electrical system. Well done! 501262

I've towed racing sailboats for many years, mostly with European automobiles. Needed the hitch later this month so I could pick up a "new" one I just bought . This install was the second easiest out of the 6th I've done myself. High quality kit fits great. Even though Curt says the C11701 doesn't work on my 2008 Mercedes E350 4Matic Sedan Sport, I had absolutely no problems. The Tekonsha light converter was a snap too. Certainly lots better than the old days when I had to jury-rig the trailer lighting to match the car. Finally, your service was super. Couldn't be happier. Thanks! 395365

Very easy installation and zero problems since. Tows the new racing sailboat great. Highly recommended.

George S - 06/12/2018

I’m happier than I thought I would be with the results. Even the nifty little 12 V tester work fine. The instructions were more than adequate, there was plenty of wire and everything worked on the first try. 566365

Installed in an afternoon, could have been under an hour with model specific instructions. The car ('16 BMW 328iX wagon) has a bulkhead connector through the passenger side rear quarter where all the tail light & other rear end wiring exits. That bundle of wires splits off a larger loom ~6" before the bulkhead, which looks to be the easiest spot to install the current sensors. It's tight access but also less than a foot away from the battery. It's all accessible by just pulling one interior panel, no need to touch the drivers side at all, installation at each taillight location doesn't make sense for this car. Oh yeah - both L & R turn signal wires are black/white, so you have to double check before buttoning things up. The product works perfectly as advertised. My only request would be for a little more streamlined shape to the sensors for tucking into a tight space like mine. 296467

by: Dale06/01/2018

Bought the hitch and wiring harness from etrailer.com last year, and following their excellent video installation instructions, was able to complete the installation in only a couple of hours. (Would take about half that time to do it again, always worried about breaking something!) Everything has worked flawlessly, and we have been completely satisfied with the purchase and support. Will definitely return the next time we're in the market for hitch related products. 515249

Product was simple and straight forward to install on my BMW X6, however, it does have some issues. The lights are inconsistent at best. The lights on my travel trailer sometimes work perfectly and some times not. The issues are that sometimes the lights just go out while traveling down the road and then come back on minutes later or not at all. When the lights won't come back on I have to pull over, turn the car off and then restart. This works to bring the lights back on. Other times the trailer lights just stay on. Turn the car off and the lights just want to stay on. Unplugging them turns them off. So.......they work......sort of. I hope this helps. 463447

Well built wiring kit and good instructions. The Land Rover's wiring is tough to get at, but after taking the spare tire out and the fuse block door off I could get at them. One thing the instructions didn't indicate is that the rear lights appear that they have to be plugged before the module will learn them. Tried the first couple times with the connector removed from the light and the module would not work. Removed the fuse, but the tail lights back in and went through the learning process and it worked the first time. 430624

Working great and never had an issue with it.

Brian S - 09/10/2018

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. 697887

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by: Mark L07/17/2019

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. 671336

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Great product! I was able to install on my BMW X5 in less than an hour, very easy installation. I placed the order with Etrailer and while I awaited its arrival I watch the video associated with the installation. When the item arrived I opened the box verified I had all the required parts and made the installation without reading the instructions. Watching the video is invaluable and well worth the time. Upon completion I hooked to my trailer and it worked flawlessly. If you follow the set up you will have no problems. I liked the fact I had to do know splicing and removal should be simple. I ran my wiring to the hitch so I didn't have it hanging out the back hatch. When I looked online it suggested the removal of the bumper cover. I was able to run mine down behind the bumper and to the hitch with out removing anything. I simple fed it behind the bumper with the tailgate down. It tucked neatly behind the bumper and I zip tied it in place. The unit seems to be well built but is a little pricey in comparison to other units. The benefit of having a universal harness that requires no splicing with easy installation was the difference maker for me. 414075

I selected this kit to install in my 2008 BMW X5 because I didn't have to splice into my vehicle's wiring and risk damaging something and it was extremely easy to install. It turned out to be even easier than I originally anticipated. Total install time was about 45 minutes start to finish. And even better, if I ever need to remove the kit from the vehicle, there won't be any trace that anything was ever installed. Difficulty level to install on a scale of 1 to 10 with 10 the most difficult is about a 2. Works perfectly as described. Highly recommend over any other trailer wiring kit available. 541233

I’ve been using this wiring harness now about a year to run several small trailers with no problems. I always check all trailer lighting afyer hooking up and no issues.

DougR - 07/13/2019

This is one of the most easiest kit to install, The instruction diagram is very clear and print really well. I honestly did not follow the instruction diagram because it is very simple and straight forward. Work so great, no wire tapping, cutting, pinching, non none of that. 482391

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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. 399189

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by: Sam W.07/25/2019

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! 675332

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The directions for installation are poor at best. Quality looking harness. I will let you know if it works once I figure out how to install it. It is a universal harness, so it won't be too specific, but more description would have been better. 516051

The wiring harness you purchased for the 2015 Mercedes-Benz GLA-class does take a little bit of wire testing to determine how to install. First you want to use the wire tester that came with the kit to test the tail light wires on your vehicle. If you cannot locate the circuit tester from the kit I would recommend purchasing one such as part # 3808
Quickee Circuit Tester
$37.71. Using the tester, you will need to locate the functions of the wires. In order to determine which wire represents which function you will need to have a friend sit in the vehicle and perform each function while you are testing the wires. After you determine the functions you want to determine what style tail light you have by using the chart in the installation instructions. Follow the chart to attach your connectors from the kit to the corresponding wires depending on what type of wiring system you have, 2 wire system, 3 wire system, Brake tail multiplexed wiring or brake tail turn multiplexed wiring.

-- Heather A - 06/04/2018

Helpful Link

I purchased and installed the 119250KIT in my 2016 Lexus RX 350- WITHOUT the factory trailer package. Although Lexus will always tell the consumer it Must have the factory wiring harness, it does not. I did not take pics but this is not a difficult task to accomplish. Be patient and follow these steps, it is about an hour long task. To install the wiring harness, first remove the plastic trim at the bottom of the lift gate, it is held down with plastic fasteners and simply pops off. I strongly suggest going to Harbor Freight and buy their $4 kit of plastic pry bars, rather than risk scratching up the paint on your vehicle. Next remove the deck storage buckets and carpeted pieces to left/right of the spare tire, this will allow you open access to the wiring. I installed the Tekonsha module on the driver's side in very back to left of the spare and on the back of the wheel well. Don't put on the double sided tape yet, this will be done in a later step. Next step is to remove the small plastic (3" x 2") vent on the rear left vertical carpeted wall, it just pops out from the bottom (first), then slide down, and off. Now, carefully remove the left tail light by using a plastic pry (from Harbor Freight) the whole assembly will slide out of the plastic snaps from front to rear. Use a towel when you let it 'hang' against your paint. There is a thin plastic cover piece which is in the lift gate track and covers 2 tail light bolts- which pops out easily. Once the assembly is removed, you will see the turn signals bulb insert has a colored (power) wire and a ground wire (twist this to unlock and allow you to test which wire is hot). The other wires on the assembly go to the running and brake lights- test them in a similar manner to determine which color is running lights and which is brake light. Look through the opening where you removed the 'vent' to see the tail light wires and pull/trace them by color into the back of the vehicle. You will have to slide the tail light wires (carefully 1 at a time) through the black water tight rubber plug to give you some length to clip on the Tekonsha connectors. I connected the Left, Running, and brake light -Teconsha clips all on the left side of the vehicle. Don't wrap the foam around them until they first test ok. All of the arrows on each Tekonsha clip should point toward the (rear) tail lights. A CRITICAL task is to locate a GOOD ground from the Tekonsha module (white wire) in the back of the vehicle. In my Lexus, under the Lift Gate area, I located a steel screw which already had 2 white wires with black stripes and extended the (short) Tekonsha to allow me to use this. Without a GOOD ground, you WILL have problems, waste a lot of time (1 hour plus), and aggravation to troubleshoot problems later. Trust me, I know!! Now that you have completed the wiring on the driver's side, do the same with the passenger side. Here you only need to run the single clip for the turn signal (1 wire). The Tekonsha clip is long enough to run across the lift gate area next to the factory harness. Locate the appropriate right turn signal wire by sliding off the right tail light similar process to the left light you just did. Clip on the Tekonsha clip. Next I tested all of the lights with my trailer. Once all were working, I put the foam wraps on each clip, secured the Tekonsha module using the double sided tape (on rear of wheel well), secured loose wires with zip ties, bundled together- all excess wiring, and secured in the side well. The last task is to run the black power wire from the Tekonsha module up to your battery in the engine compartment. If you are not too large, you can fit under the vehicle- otherwise raise it off the ground (safely) so you can get under the left side to route the wire. First, disconnect the negative battery cable from the battery post! Next, I loosened the 6 bolts which held the black plastic covers (under carriage of RX 350) and ran the wiring from just in front of the LR wheel all the way forward to my battery. Zip tie along the way as necessary, as not to interfere with moving parts. Then from under the vehicle, I ran the remaining wire around the LR wheel and zip tied again as not to allow any pinch points or abrasion (from suspension) of the wire. In the LR quarter panel of inside of vehicle you will see a rectangular brown plastic which will pop out and allow you access to pass wires from the undercarriage to the inside. This is where I ran the power (to battery) and trailer light 4 wire pigtail (to hitch area). Since it is plastic, I cut out a little square in the bottom of it and reinserted this in original place. Next, go to the front of the vehicle and install the fuse holder to the positive side of battery. Reconnect the battery ground and insert the 15 amp fuse provided. Give your system another check and verify the fuse did not blow. Put back the removed panels and pieces- you are all set to tow!! 278814

Great service... due to package damage I was missing the pin for my hitch.. they sent another immediately 912686

by: John W11/12/2020

The wiring harness worked great, without having to tap into existing wiring. The only reason I didn't give it five stars is that occasionally the trailer lights don't match up with what the car is doing when I first connect it. However to correct this all I need to do is pull the fuse on the wiring harness and plug it back in, and the unit will relearn the way it's supposed to work. 911130

by: 11/12/2020

911070

I’m not a mechanic, but installation looks easy. Having it installed next week 910662

by: 11/06/2020

908673

Combine this kit with a couple of YouTube videos (Thank you U-haul), the installation isn't difficult. Do purchase a circuit tester with an attachment that wraps around a wire and pierces the insulation. The cheap circuit tester that comes with the kit is worthless. 903709

by: Better than expected10/06/2020

Works better than expected. No "learning required by device. Works fine when powered up, even though i normally remove power between trailer uses to eliminate load. 898099

891679

I received the trailer hitch and wiring extremely fast. I had the hook up made today and the hitch looks great. Great price and service! Thank you Greg! 883463

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