Relay works with your tow bar wiring system to ensure that your towed vehicle's turn signal lights flash in tandem with your RV's lights.
Features:
The purpose of a brake light relay kit is to prevent your towed car's brake signal from overriding the turn signal that comes from your RV. When your towed vehicle is properly wired and connected to your RV, its indicator lights will illuminate as you engage the turn signals in your RV. However, if you have only a four-diode system in place, the turn signal will be overridden by your towed car's brake signal as soon as your supplemental braking system presses the towed car's brake pedal. As a result, drivers behind you know only that you're slowing down and not that you are turning.
Installing a brake light relay in your towed vehicle fixes this problem by ensuring that your car's brake signal does not override the RV's turn signal. Therefore, your towed car's lights will function in accordance with your RV at all times.
Is a Relay Required?
To determine if a brake light relay is needed to properly wire your vehicle to be towed, answer the following questions.
Are you using a supplemental braking system that depresses the brake pedal in your towed car?
No - You do not need a brake light relay.
Yes - You may need a brake light relay. Continue on to the next question.
Do the brake lights on your towed car illuminate while the engine is off?
No - You do not need a brake light relay.
Yes - You may need a brake light relay. Continue on to the next question.
Do your towed car's brake lights act as both the brake signals and the turn signals?
No - You may need a brake light relay. Continue on to the next question.
Yes - Your towed car has a combined lighting system. You will need a brake light relay to ensure proper activation of its signal lights.
Does your towed car have separate brake lights and turn signals?
No - Your towed car has a combined lighting system. You will need a brake light relay.
Yes - Your towed car has a separate lighting system. You may need a brake light relay. Continue on to the next question.
Are you wiring your vehicle with a six-diode kit or a TowDaddy custom wiring harness?
No - You will need a brake light relay to ensure proper activation of your towed car's signal lights.
Yes - You do not need a brake light relay.
Most towed cars require the normally open installation method. Ford and Lincoln models with neutral tow kits and most automobiles that have a push-button start function will require the normally closed installation.
Normally Open
The diagram and steps shown below demonstrate the installation for normally open applications. Be sure to follow the instructions included with your relay kit for a more detailed process.
Normally Closed
The diagram and steps shown below demonstrate the installation for normally closed applications. If you have a Ford or Lincoln that has a neutral tow kit or if your car has a push-button start feature that will not start the engine when the brake fuse is removed, then you need to perform a normally closed installation. Be sure to follow the instructions included with your relay kit for a more detailed process. Normally closed operations may require additional connectors and length of wire that are not included with this kit.
Average Customer Rating: 4.8 out of 5 stars (193 Customer Reviews)
Relay works with your tow bar wiring system to ensure that your towed vehicle's turn signal lights flash in tandem with your RV's lights.I used this relay along with a separate switch to turn on Firestone air suspension compressor. Remember always use electric grease on connections. Thank you etrailer. God bless. Jesus saves.
Evidently Roadmaster had made some slight alterations from the depiction, for the better. The fuse wiring was a spade end with two fuse holders built in. The holder closest to the spades was for the original circuit and the other for the new circuit. This was very handy. I had watched the installation video and thought it would be fairly easy; therefore I attached the terminals to the green, black, and white wires before even going to the CR-V. I did however purchase different spade connectors as I thought I may want to remove the brake relay switch in the future for another vehicle should I trade. Also the yellow connector is quite large and the video showed bending the wire over itself so that it would hold on the smaller wires. This was a wise decision. What was the problem was the wiring in my CR-V. The video showed similar size wiring from the brake switch. What I found was smaller wire, loomed very close to the brake switch. Evidently Honda had made some modifications. I believe the wire was 22 gauge and there was no real way the blue or yellow connectors would have worked. That said, after disconnecting from the switch, stripping the loom back to get some exposed wiring, cutting and using the 22-16 gauge connectors, drilling a hole for the ground screw, etc. the switch worked perfectly. I did vary the fuse location from the 7.5 Amp #29 Occupant Detection System (ODS) to the 15 Amp #28 Washer as I figured it would less likely interfere with any operation.
Richard - 10/24/2018This can be a rather difficult installation for a do-it yourselfer but thanks to the etrailer instructions and video any handy person can accomplish it. Just make sure you watch the video and do it exactly as instructed. I downloaded the video to my laptop and put the laptop on the front seat of my F-150 so I could follow their step by step procedure and avoid doing any damage to my dashboard when disassembling it.
James D - 02/27/2021Self installed on 2018 Ford F150. Had issues due to cutting into very thin brake light switch wire. Bad connection created issue where truck would not come out of park. Use extra care when tapping into that wire. Also included fuse tap didn't work with 2018 F150. A micro mini fuse tap is required.
From all of the positive reviews I'm sure this product works well for most people, but it didn't work well for me. Not much positive about this product except it did work after 2 days of trying to get the wiring sorted out. I ended up with two butchered wires because the installation instructions were incomplete and contained errors. I bought this for the plug and play since I could have bought all of the parts in the kit for less than $10 and figured out the wiring on my own, which I had to do anyway. Anyone with a 2010 Base Honda Fit should note that if you have a green/silver wire (kit instructions say to use for relay) and a green wire on a common terminal off the output of the brake light switch, you should be prepared to cut the green wire to install the relay. I can't say all are like mine because I understand that many have only the green/silver wire off the brake switch.
Joseph S - 07/02/2020The installation video for the 2011 Honda CR-V was excellent and I used it to install the Brake-Lite Relay Kit on my 2012 CR-V. However, the picture of the kit at the beginning of the video was very misleading. It didn't show the fuse holder or the fuse talked about in the video, instead there was a yellow component pictured that had no relation to the installation or the actual kit that I received. Fortunately all the necessary parts were in the kit I received and the installation went just as the shown in the video. It works as described.
John F - 07/24/2020
I truly enjoy travelling with my MH and Roadmaster RM-88400 tow bar and braking system. I can stop wherever I like and unhook and be gone in 5 minutes. When finished site seeing or shopping I can be hooked up and on the road just as fast. Great system.
Bill M - 06/22/2020Not too hard, once wired right it's great. My advice, drop the provided blue butt connectors and use bell caps or something more reliable. Also the crimp on ring for ground was 1 size too small for my 2007 CRV. In the video for the 08 CRV the technition added an additional black wire to the brake unit. If you have an RVI3 brake you will not need the additional wire. If you use a brake system like an RVI3 wireless brake, this will keep blinkers blinking when braking.
Great product that has everything needed for a simple install. Well, it is always interesting getting to the tiny wire on the brake light switch up under the dash, but I got it done!
I installed this on my towed vehicle about a year ago. The initial installation went well and the instructions provided the necessary information on installation. After a year, I have not had any issues with the equipment and the car's break lights work as expected as both a driven vehicle and a towed. There are a number of ways to setup a towed, and once I decided on using the vehicle lights rather than a light bar, this kit was kind of a no-brainer. Also, during the past 12 months I have purchased additional items from etrailer and have always been satisfied with both the products purchased and the support from etrailer.
Robert M - 02/04/2020Have a issue with 2016 Wrangler. Before install the brake light works anytime, even without key. After install the brake lights only work in the On/Run position (not in Accessory position). I use the Even Brake system which requires a brake signal, thus I have to set the ignition switch to On when I am towing which means the odometer will count the miles and who knows what could be damaged by leaving the ignition switch turned to On for several hours. This relay does exactly what it says, but I would prefer that it work in the Accessory position which is what is recommended in the Jeep manual for towing.
This works perfectly and have driven several thousand miles with it. The installation did not work as specified. My model Jeep - a 2016 Cherokee with Active Drive II has two green wires with light green stripe, neither of which worked as the bypass. I tried it myself and took it to two mechanics; neither could find the correct wire or would attempt the work. I finally installed the relay in the fuse box. In my car, the brake light fuse is paired with the gas cap release in a micro3 (ATL) socket. This saves space in the fuse box for the manufacturer. The center pole is a shared hot for each of the two circuits. I installed a micro2 (ATR) fuse holder that has space for two ATR fuses (similar to the one supplied but has space for two fuses, not one). In the lower fuse holder socket, I installed a 10A fuse for the gas cap release. In the upper socket, I installed a 10A fuse for the the relay. I attached the blue relay wire to the red pigtail of the fuse holder. In the brake light side of the fuse box I installed half of an ATR fuse along with a tin fuse tap. I attached the black relay wire to the fuse tap. Finally I attached the red wire to the always hot wire on my 6-pin socket. This ensured that the relay is active as soon as I plug the Jeep into the motorhome. All the parts are available at a local auto parts store. Wiring this way took less than an hour, did not require cutting the brake light wire under the dash and *may* prevent voiding the warranty, although I did not verify this.
This review is for E-Trailer. I ordered a complete dinghy towing set-up for the dinghy as a towbar came with the RV we purchased. I called E-Trailer and spoke with a very knowledgeable young lady and when I told her what I needed in layman’s terms she came up with what I would need to complete the dinghy preparation in order to safely tow it behind our RV. Everything they said it would do went just as the instructions directed. I ordered a Roadmaster Falcon 2 set up for the dinghy and they suggested a Blue Ox self contained braking system for the SUV itself. hey also suggested the complete wiring system and plug for the dinghy. To my amazement after the RV and dinghy were connected that also was as easy as they said it would be. Our first tow with the dinghy was great and the unhooking was also a very easy experience. This company was awesome to work with. Thank you for your knowledge and great products.
Had to get help from etrailer in this but eventually got it done
Worked out great just not easy for an old man to get under dash to install. I really like that e trailer has videos showing install of their products.
worked like a charm, instructions well done
Justin B. was extremely helpful, answered my questions & checked the vehicle model to find I also needed a brake light relay. The shipping was on time also. Great place to deal with. Thanks Justin
Website video made for an easy install and has worked great for the last year.
I ordered all the parts required to safely flat tow out 2017 Jeep Cherokee Trailhawk from etrailer.com. The only part they didn't have was the Mopar Flat Tow Enhancement kit Jeep requires to flat tow this model. Ordering from them was great, the website is easy to use and I was able to locate all the pieces compatible with my specific vehicle. The expert recommendations help my decision choosing the right parts. I ordered from etrailer even though I found some of the parts on other websites a little cheaper. I chose to pay a little more because of all the effort etrailer has put into installation videos and guides. I was very pleasantly surprised to learn from etrailer that they have a price match guarantee! So my equipment consisted of the following Mopar Flat Tow Enhancement Kit (from Jeep) Roadmaster Battery Charge Line Kit for Towed Vehicles Mighty Cord 7-Way RV Style Trailer Connector - Trailer End WesBarg 7-Way, RV-Style Connector w/ 6' Long Coiled Cable Trailer End Pollak Black Plastic, 7-Pole, RV Blade-Style Trailer Socket - Vehicle End Hopkins Custom Tail Light Wiring Kit for Towed Vehicles SMI Stay-IN-Play DUO Supplemental Braking System Roadmaster Brake-Lite Relay Kit for Towed Vehicles Blue Ox Alpha Tow Bar - Motor Home Mount - 6,500 lbs Blue Ox Base Plate Kit - Removable Arms Blue Ox Tow Bar Cover - Aladdin, Aventa LX, Aventa II The installation videos are great but not all inclusive. Take the time to read the instructions that come with the parts. This is a major project, I took about 30 hrs over a full week but as you'll see in the pictures I took s few extra steps to make a cleaner look. Some of those extra steps: The base plate install requires the bumper be modified cutting off a flange on each side, I spray painted this to prevent corrosion. In the install video of the baseplate on the drivers side they use an extra quick link (not included) to run the safety cable around the wiper fluid reservoir. I took the time to remove it and run the safety cable behind it. I didn't want our nice new vehicle to look like it can be towed so I played the brake away switch and 7 way trailer plug behind the license plate, so when not being towed our vehicle looks great! Some things to be aware of. The Brake air cylinder that mounts to the brake pedal with four bolts may need longer bolts, it did on our Jeep. Spend the money for weather tight heat shrink crimp fittings. The Hopkins wire harness was about 1.5 feet short to get to my plug location. Buy extra zip ties, electrical tape and split loom. I recommend reading all the various installation manuals and watching all the videos because the various components integrate together and if you install one at a time you'll be doing a bunch of extra work. The brake light relay is a real pain in the butt, not because of the hardware but because of the location of the brake light switch which is very hard to get to. Overall I am very happy with the products and how the installation looks. We haven't towed it yet but do not expect any problems.
Roy - 07/30/2018Good quality. Good instructions. Difficult to install only due to the tight quarters inside the Jeep. Works great.
Pulled entire length of route 66 and then some. We had absolutely no issues with all of our etrailer equipment. Thanks for all of your help.
I have a 2016 Jeep Wrangler Sport Unlimited 4 door, after I installed the Hopkins Custom Tail Light Wiring Kit for Towed Vehicles - HM56200, I found I had to install the Road-Master Brake Lite Relay for Towed Vehicles - RM-88400 , I'm using a supplemental brake system, when the brake is depressed with ignition off, the brake lights come on and cancel out any directional signal on my toad, installing the relay solved this problem. I watched the video and this was helpful. Installation took me a few hours, climbing under the dash was not an easy chore for me, I'm not as young as I want to be, had to purchase 16 gauge Red wire to run to Fuse box under the hood, also I recommend having extra wire ties to do this. I recommend both products, easy to install and good quality.
Rich L - 11/13/2017I have now installed the following on my 2017 Wrangler: Brake light relay kit . Hopkins Towed vehicle Tail Light wiring kit. Blue Ox base plate. Blue Ox Patriot Portable RF Braking System. All of this has taken about 3 days of work spread out over a week or so. Overall it went well. Not too many surprises. Crawling around under a car at 71 is a bit of a strain but I'll get over it. I must say that Donna P. has been a wonderful source of great information and has stayed right on top of the process. eTrailer has been a great source for this project. I would recommend you all with no hesitation.
John M - 06/15/2018Works as advertised.
Lutz M - 05/09/2021I love the quality of the products I ordered. Customer relations was very good as well, they kept me informed and even though it took several weeks and etrailer had to wait on items to get to them, I was communicated to well. I know it’s important in who you deal within this day and time and you can trust etrailer.
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