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Trailer wiring problems can cause big headaches if they affect your vehicle’s electrical system. This harness uses a powered converter that takes power directly from the battery instead of the vehicle’s light circuits. If a short happens on the trailer, it won’t knock out the vehicle lights or damage its wiring. The converter also combines separate turn and brake signals so your trailer lights work just like they should.
You don’t have to cut into the factory wiring to get towing lights. The harness plugs into existing connectors behind the rear panels, using matching plugs for each side. Just disconnect the taillight plugs, snap in the Curt connectors, and route the harness to the converter box. The 4-flat connector comes ready to use for running, turn, and brake lights.
The included black power wire runs from the back of the vehicle to the positive post on the battery. This direct feed keeps trailer voltage separate from sensitive factory circuits. It also makes sure the harness gets consistent power for all lighting functions. The fuse holder at the battery adds extra protection against overloads or shorts during use.
Grounding can be confusing on some installs, but this harness keeps it straightforward. The white ground wires are already built into each connector and tie into the factory taillight grounding points, so no extra mounting or drilling is needed. Once everything is plugged in, the grounds are complete and ready to go.
The 4-way flat plug gives you all the standard lighting functions—running lights, left and right turn signals, and brake lights—so any basic trailer can be connected without extra adapters. It’s a clean, reliable setup that works for most light-duty towing needs.
Customer Satisfaction Score:
86% were satisfied with this product
14% of customers were not satisfied
Ratings & Reviews
Good quality wire harness. All the parts are included. The instructions are clear.
This wiring harness installed well. The installing instruction video was excellent. It made installing the harness easy.
Great Job Etrailer.
Excellent product! Installed as described in the instructions included with the product. Would buy this product again.
The website was very easy to navigate. The videos to show insulation were very helpful. The additional information in regards to additional recommended products was helpful. I would recommend this to anybody looking for a light kit and hitch system.
Very happy with this product.
100% satisfied......excellant hitch...bolted right up...easy peezy...wiring harness right on the nuts, took a bit to string it but with some backyard mechanical ability you can git-er-done 2006 Lexus 360
The kit had everything needed to set up wiring. Quality materials and good instruction. Snap fit at the light connections made it fool proof. The toughest part of the project was routing the wire to the battery, but the wire was extra long so one could route it s number of ways. I chose to go over the gas tank. Highly recommend.
If it is a DIY application, etrailer is my go to source forever. I added a towing/hitch system to my 2004 Lexus RX 330 in the Driveway. Easy install.
Great product - My vehicle is a 2004 lexus rx330 which required a long wire all the way from the battery back to the rear lights . Care must be taken as the wire is routed to make sure that there is no chance of the wire rubbing on anything over time and wearing through , which would then blow a fuse or worse . Despite that concern , I've no problems at all .
Thanks , John
Nice hitch. Exactly as the web described. Easy installation even for a single person lying on the floor of the garage. Wiring harness fairly easy installation even though it seemed a little shorter than displayed in the video. Double face tape would not stick even after cleaning car with alcohol. Wire tied to car wiring for installation just as well.
Purchased self tester and would recommend this for a lone person installation. All total took about 3 hours.
When I first opened the box and saw how sturdy and heavy this received was, I thought maybe I was in over my head doing the install myself. However, I was able to easily balance the receiver on a spare tire/wheel I laid on the ground in the middle/back of my vehicle. That allowed me to easily lift the unit high enough t get a bolt started the muffler side, then it was a simple matter of installing the rest of the bolts, it took me no more than 20 minutes, including removal of the old tie-down brackets. I towed with it today, everything is great. I also learned that my 2007 Lexus RX350 came pre-wired for a trailer, all I had to do was tear off some interior trim, the wires were clearly visible, I cut off the proprietary connectors and sliced in a 4-wire cable. I'm not sure if they call come this way.
etrailer had the exact information I needed on how to order and get the product(s) I needed. Very easy to find, understand, order and receive. Everything went great
R.p. R.
4/29/2021
Great-just what I needed and wanted
This was the first time I had ordered a product from etrailer and my experience has been awesome. I started by googling a hitch for my 09' Lexus RX350 and wasn't sure if such a thing existed. etrailer was the first on the search engine. The website made it easy to navigate what products I was looking for.
I was looking for a complete kit which included a custom fit hitch. Browsing through the website and reading through the descriptions, I found out that I also needed a wiring set. etrailer made it easy to search for wiring kits with great prices.
The wiring kit came in the exact time frame along with the rest of my order and still in factory packaging. I am thankful for the instruction videos that etrailer provides because that made the installation that much easier. Me and my father followed the instruction video step by step and was able to have the wiring installed in about 30 to 45 minutes. I read from previous reviews that the length of the battery connector might be short but in my case, it was more than enough to reach the battery on my 09' Lexus RX 350.
This is my first wiring kit and although I haven't used it, I'm excited to try it for my move in the next two months. Overall, great product with easy installation. I'd recommend it to anyone wanting to get it for your 09' Lexus RX350.
I installed the wiring harness part # C55563 for the 2008 Lexus RX350. I watched the video which was specific to my vehicle and had a good idea of how to proceed. By following each step as it was explained I was able to complete the install in about 4 hours. It took me longer than most people because I had to keep going in the house and looking at the video. I was very happy with the way everything went together and pleased that all parts that I needed were included. It is a little hard working in confined area around the taillight but take your time and don't be afraid to pull back on the trim is needed. It is also good to have a trim tool to pull the push pins and have some extra push pins on hand in case you break one.
I hooked it up according to the directions, but it didn’t work. The rear taillights stayed on all the time with the exception of the main right taillight.
Lazer S.
4/28/2026
Sorry to hear it's not working properly, Lawrence. Couple things to check. First, make sure everything is plugged in all the way and fully seated/snapped together. Second, make sure your ground is on a good clean metal surface that is not aluminum. I would also make it has its own ground source and isn't stacked with other grounds. I honestly think you are having a grounding issue as almost 100% of the time we hear something weird happening, that's the cause. I would say what you are experiencing is also weird. Let me know if either of those fixes your issue.
E-Trailers did a great job of making this process easy! The video of their installer putting this exact kit in my exact car was so well done that even I could do it safely and competently. My car became so much more useful in just a couple hours that it’s probably one of the best investments I’ve made in years. Thanks, eTrailer for the great product, quick service, great communication and attention to detail!
Carole
10/8/2023
To update: after a year, it’s still meeting and exceeding my expectations. Thanks again!
Andrew N.
10/24/2023
The harness was for a Lexus 2004 RX330. A local auto detail shop did the wiring, as electrical is a DIY area that I don't enter. They installed it one afternoon in August 2021. It has operated the lights on a small boat trailer over a number of mountain passes and at lake launch areas without any glitches. Nice!!!
Really like the website for searches and support videos, knowledgebase info. Emphasis on competent, thoughtful customer service. I'll order here again.
Kcr
11/19/2023
Still faultless.
Very simple to install on my 07 Lexus RX350, just a little time consuming.
fits perfect
Poor engineering
Requires a external ground but none is supplied
Required a power wire from the battery all the way to the trunk that’s just dumb I’ve never had too pull a power wire to install a 4 way plug.
Customer service is awesome, I would highly recommend etrailer.com to anyone needing great products and service. Very responsive and helpfull
Plug n play. Very straight forward and easy to install
Plug and play for 2009 RX350. Except for wire to battery. Did this on my driveway with no jack stands. Ground clearance made it difficult. Highly recommend some jack stands.
Defective. Only 5 volts output. Converter box is bad.
After one year, I think this was a good investment for my RX 350. I’ve used it several times now for various reasons, mostly towing my motorcycle. It was super easy to install and has held up pretty good so far. The only recommendation I have is to run your wiring from the interior fuse box with a fuse tap, rather than running it under the car from the battery. Running the wiring along under carriage just seemed like a bad idea long term. Just use one of the cigarette lighter fuses in the fuse box to tap onto and route the wiring along the interior panels. The hardest part is getting past the rear seat. I recommend using a wire hanger for this part. Great product overall!
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Dale
5/6/2022
It is working perfectly!