Hopkins Custom Tail Light Wiring Kit for Towed Vehicles

Hopkins Custom Tail Light Wiring Kit for Towed Vehicles

Item # HM56204

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Tow Bar Wiring

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Tow Bar Wiring HM56204 - Custom - Hopkins
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Product Images

In Use/Installed

  • Wiring Harness
  • Plugs into Vehicle Wiring
  • Hopkins
  • Tail Light Mount
  • Custom
Wire your vehicle and get the signal lights required for flat towing without having to splice into your wiring with this custom, plug-in harness. Integrated diodes prevent feedback from RV for safe operation. Wires as combined lighting system. Lowest Prices for the best tow bar wiring from Hopkins. Hopkins Custom Tail Light Wiring Kit for Towed Vehicles part number HM56204 can be ordered online at etrailer.com or call 800-298-8924 for expert service.

  • All Info
  • Reviews (7)
  • Q & A (14)
  • Videos (3)
  • Photos
  • Why etrailer?

Hopkins Tow Bar Wiring - HM56204

Wire your vehicle and get the signal lights required for flat towing without having to splice into your wiring with this custom, plug-in harness. Integrated diodes prevent feedback from RV for safe operation. Wires as combined lighting system.


  • Lets you wire your vehicle to accept your RV's tail, brake, and turn signal lights for flat towing
    • Wires towed car as combined system so that brake and turn signals travel along same wire
    • Provides 4-way flat plug at front of towed car to connect to motor home
  • Plugs in quickly and easily - no cutting or splicing of wires
    • Connection points are located behind your vehicle's tail lights
  • Prevents electrical feedback to safeguard towed car's electrical system
    • Weatherproof box keeps built-in diodes protected
  • Won't interfere with electrical system when towed car is not hooked up to RV
  • Custom designed for your vehicle
  • Includes wiring harness, mounting bracket, and installation hardware
    • Extension loop for connecting towed car to RV is sold separately
    • Brake light relay (RM-88400 - sold separately) may be required if used with supplemental braking system
  • 90-Day warranty

Wiring Your Towed Car with Hopkins

Wiring your car for flat towing has never been easier. No more testing wires or splicing into your electrical system. No need to painstakingly position multiple diodes beneath your vehicle. No worries about voiding your warranty. With this custom-fit towed vehicle wiring kit from Hopkins, all you have to do is plug the harness into your vehicle's existing wiring, which is located behind your car's tail light assemblies. No cutting, tapping, or splicing is required.

After plugging in the wiring harness, use the included bracket to mount the 4-way flat connector at the front of your towed car. An extension loop (sold separately) is required to connect your towed car to your RV.

Changing from a Separate to a Combined Lighting System

Your vehicle ordinarily operates on a 3-wire system, wherein the brake signal and the turn signals travel along different wires to illuminate different lights. (Typically, this means that your vehicle will have amber turn signals.) This is referred to as a "separate lighting system." When you hook up for flat towing using this harness, however, your towed car's lighting system will operate in a combined fashion. This means that the brake and turn signals sent by your RV to your towed car will be carried on a single wire. As a result, your car's brake lights will do the flashing for the turn signals. Your vehicle will still function as designed - with separate lighting - when not hooked up to your RV.

Do You Need a Brake Light Relay?

Because this harness wires your vehicle as a combined system, a brake light relay (RM-88400 - sold separately) may be required if you use a supplemental braking system with your towing setup. A supplemental braking system depresses the brake pedal in your towed car every time you apply the brakes in your RV. So, if your towed car's brake lights illuminate when the brake pedal is pressed and the engine is off - as is the case when towing - then you need to install a relay to ensure that the lights on your towed car always act in accordance with the signals sent by your RV via the wiring harness. Without a relay, the brake signal from your towed car will override the turn signal sent by your RV when you slow down to make turns, creating a potential hazard.

11156204 Hopkins Plug-In Simple Dinghy Towing Harness

Replaces Tow Daddy 3008 and Hopkins 56204

This Product Fits The Following Vehicles

2008 - 2012 Jeep Liberty

Video of Hopkins Custom Tail Light Wiring Kit for Towed Vehicles

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Hopkins Tow Bar Wiring - Plugs into Vehicle Wiring - HM56204 Review

Today we're going to review part number HM-56204. This is the Hopkins custom taillight wiring kit for towed vehicles. This part includes everything shown here on the table, it will include the wiring harness with the converter and the T-connectors and the length of wire with the four-way and the dust cap all included. The mounting bracket and the installation hardware for the four-way are also included, a ground screw for connecting the ground, some cable ties for taking up any slack in the wiring, or for mounting the converter box, and also a nice package of dielectric grease to apply to all your electrical connections. This part will let you wire your vehicle to accept your RV's tail, brake, and turn signal lights for flat towing. This wires the towed car as a combined system so that the brake and turn signals will travel along the same wire, and it provides this four-way flat plug at the front of the towed car to connect to your motor home. When you install this it does plug in quickly and easily, there's no cutting or splicing of wires.

It uses these T-connectors, this to go to the passenger side with the green wire, the yellow wire is for the driver's side, you just plug these inline to the wiring harness. The connection point is usually located on the vehicle's taillights. The converter right here, this will prevent electrical feedback to safeguard your towed car's electrical system. This converter has a weatherproof box that will help keep the built in diodes protected. This part won't interfere with your electrical system when the towed car is not hooked up to an RV. It is custom designed for your vehicle.

We do recommend to use with this at the front your car. You're going to need to plug this four-way to your RV, so we do require an extension loop for connecting this towed car to the RV. We do sell those separately on our website, they are listed as a related product. One of them is a HM-47115, and it again is listed on this product as a related product. Now, you do want to remember that because this harness will wire your vehicle as a combined system, you might need a brake light relay if you use a supplemental braking system in your towing setup.

We do again sell that separately on our website, and again it's listed as related product on this product page, it's part number RM-88400, and the relay is used to ensure that the lights on your towed car will always act correctly with the signal sent by your RV using this wiring harness. Just briefly, how this would install. What you'll do is go tot he back of the towed vehicle behind the taillights, and these will plug inline. You unplug the wiring harness from the taillights and plug these in, and as I mentioned, the yellow wire will signify or designate that this is the driver's side, the green wire is for the passenger's side, so you plug those in. Your converter, you probably want to attach to a nice flat surface so it doesn't bounce around. You can use the cable ties to run through here to hold it into place.

Then this length of wire here, you'll run this up to the front of the car and your four-way will be positioned at the front. Again, it includes this nice mounting bracket and the hardware that you can install at the front to hold the four-way into place. Once you get this to the front, you want to take this length of white wire with the eyelet on it, that's for ground. You do want to make sure this is grounded. If there's one nearby that you can use, go ahead and use it, if not, they give you a grounding screw that you can drill a hole and make your own ground. Then, again when you make your electrical connections you might want to put a little bit of the electrical grease on there to help prevent any corrosion. Once this is all installed then you'll be able to plug this right into your RV, and your lights on your towed vehicle will work inline with the RV that's towing it. But that should do it for the review on part number HM-56204, the Hopkins custom taillight wiring kit for towed vehicles.

Customer Reviews

Hopkins Custom Tail Light Wiring Kit for Towed Vehicles - HM56204

Average Customer Rating:  4.9 out of 5 stars   (7 Customer Reviews)

Wire your vehicle and get the signal lights required for flat towing without having to splice into your wiring with this custom, plug-in harness. Integrated diodes prevent feedback from RV for safe operation. Wires as combined lighting system.

- HM56204
2012 Jeep Liberty

I purchased this harness for our 2012 Jeep Liberty so we could tow it behind our motorhome using the jeeps own tail lights for brake and turn signals. The harness works perfect and was a easy plug and play install with the exception of having to install one self-tapping screw for the ground (included). It also comes with a plastic bracket to in install the 4 flat connector on the front of the jeep which also works well! My only dislike is the wires of the harness are not incased in any form of wire loom to protect them from the elements or rubbing on other parts of the jeep which could easily damage the wires so I purchased some 3/8 and 1/2" wire loom and installed it my self but other than that it seems to be a great harness! 428726

- HM56204

Very well made, so easy to install. Thank You 477177

- HM56204
2012 Jeep Liberty

order called in at 3:20 one day, and received order by 5:00 pm the next day . Wow that was fast. Keep up the good work. I will use you guys every time I need anything. as a matter of fact I am working on another order as of today. Thank you all. Jerry A in NE MO. 420142

- HM56204

Great Product 338786


Thank You for the follow up that means a lot about you company in how youcare, another reason why I like to deal with your company. GREATCUSTOMER SERVICE! ! ! ! Still love them all working GREAT!!!

Frankie - 02/05/2018


- HM56204

easy to install and looks great... 320958

- HM56204

Exactly what I needed. Very fast shippi ng! 304291

- HM56204
Jeep Liberty

I recently purchased a Blue Ox tow bar, towed vehicle brake system and three wiring harnesses for towing my Jeep Liberty with our motorhome. etrailer.com was my first choice for the purchase for these items worth almost two thousand dollars. Even though these prices were set by the manufacturer, I knew I could trust these folks. Their salesmen, (in this case Wayne H.), are more than just order-takers. They know what they are selling and are a good source of information on a variety of related products. When Wayne wasn't available for follow-up discussions, the operator took my cell number. Surprisingly, Wayne got back with me right away and supplied me with his direct line in case I had any questions. I've had experience with others dealers who don't get back for hours if at all. Bottom line: etrailer.com will continue to be my first choice for RV and other related items. 178124


Ask the Experts about this Hopkins Tow Bar Wiring
Do you have a question about this Tow Bar Wiring?

  • How to Flat Tow a Second Generation Jeep Liberty 2008-2011
  • In order to flat-tow a second generation (2008-2011) Jeep Liberty with all four wheels on the ground you will need a base plate kit, tow bar, flat-tow wiring harness, safety cables, supplemental braking system, and possibly a high-low adapter. I have attached my recommendations for each of these parts below. For a base plate kit I recommend the Roadmaster Base Plate Kit part # 521434-1 if you have a have rock guard or skid plate excluding Renegade, part # 521433-1 if you do NOT have...
    view full answer...

  • Recommended Base Plates for 2012 Jeep Liberty to Use with Roadmaster Sterling Tow Bar
  • If your 2012 Jeep Liberty doesn't have a rockguard or skid plate then I recommend the Roadmaster EZ Base Plate Kit # 521433-1. If you do have a rockguard or skid plate then you will want the Roadmaster EZ Base Plate Kit # 521434-1, which will actually replace the rockguard/skid plate. Both of these options are directly compatible with your existing Sterling Tow Bar. Your current Roadmaster InvisiBrake # RM-8700 will also work great with your Jeep Liberty. If you are using a lighting...
    view full answer...

  • Parts Needed to Flat Tow a 2012 Jeep Liberty Sport Latitude with Falcon 5250 Tow Bar
  • The Roadmaster Falcon 5250 is compatible with the quick disconnects and all Roadmaster base plate kits. There are a few options for your 2012 Jeep Liberty depending on how it is equipped. If it does not have a rockguard or skid plate then use # 521433-1. If it does have a rockguard or skid plate use # 521434-1. I have included links to the instructions for the first set and a video install of the second set. In addition to the base plates and tow bar you will also need safety chains...
    view full answer...

  • Recommended Custom Tail Light Wiring Kit for Flat Towing 2011 Jeep Liberty
  • The Hopkins Custom Tail Light Wiring Kit for Towed Vehicles # HM56204 is a confirmed fit for your 2011 Jeep Liberty. It has integrated diodes to prevent feedback for safe operation and plugs right in to your victory wiring and the tail lights of your vehicle. Your vehicle does not require a battery disconnect kit.
    view full answer...

  • Recommended Taillight Wiring Harness for Flat Towing 2012 Jeep Liberty Behind Motorhome
  • The Hopkins # HM56204 is a plug-and-play wiring harness that contain diodes to prevent feedback into the tow vehicle's wiring system. The harness would use the taillights of your Liberty like a combined system. When the vehicle's being flat towed, the red taillights will act as the stop, turn and brake lamps. When the Liberty is unplugged from the RV and driven normally, the taillight system will operate as usual.
    view full answer...

  • Are Roadmaster Base Plates Compatible with a Reese Tow Bar for a 2012 Jeep Liberty
  • The Roadmaster base plates, # 521434-1, will work with a Reese tow bar as long as it is Reese model 74950 and you use adapter # RM-025 with quick disconnects # RM-201. If it is a different model tow bar then it will not work. based on my research I found that the compatible Reese tow bar is only rated for 5,000 pounds so it is not likely the base plates will be compatible. For a compatible tow bar you can use the Tracker # RM-020 and you will also need the quick disconnects # RM-201....
    view full answer...

  • Parts Needed to Flat Tow a 2012 Jeep Liberty Behind a Motor Home
  • Flat towing a vehicle requires specific equipment to tow the vehicle safely and in accordance with local, state, and federal laws. A front mount hitch is not suitable for use to flat tow a vehicle behind an RV but I can tell you all of the parts that you will need. There are at least 5 items you will need to flat tow your 2012 Jeep Liberty: base plates, tow bar, safety cables, lighting, and supplemental braking. But the first thing to check is the vehicle owners manual to make sure your...
    view full answer...

  • Can Tow Wiring Harness And 4-Way T-One Harness Both Be Installed At The Same Time
  • You should have no problem installing both the Hopkins Custom Tail Light Wiring Kit, part # HM56204, and the T-One Vehicle Wiring Harness, part # 118554 at the same time. It should make no difference which one is installed first, but you will want to make sure you have plenty of room behind the tail light for both harness connectors, and make sure you test the first installation with a circuit tester like part # 40376 before wiring the second harness. This way you will know all of the...
    view full answer...

  • Tow Bar Wiring Recommendation for a 2007 Jeep Liberty
  • For your 2007 Jeep Liberty the tow bar wiring harness is the # HM56203, the # HM56204 is for the newer generation Liberty that starts in 2008. To determine if you would also need the brake light relay part # RM-88400 (price at link below) you will need to 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...
    view full answer...

  • Parts Recommendations For Flat Towing 2012 Jeep Liberty Sport Behind A Motorhome
  • You will want to check with your local DOT to make sure you can tow a vehicle with a scooter carrier and scooter attached to the rear of your 2012 Jeep Liberty Sport. I recommend the Blue Ox Base Plates, part # BX1131. This bolts to the chassis and requires no welding for installation. The tabs are easily removed for a more inconspicuous look, and includes all the necessary hardware for installation. I have attached an installation video for these base plates on a 2012 Liberty you can...
    view full answer...

  • Can Tow Bar Wiring Harness be Bypassed on a 2012 Jeep Liberty
  • Do you want to bypass the converter because the RV uses separate turn signals and brakes lights like the 2012 Jeep Liberty or for some other purpose? The converter box in a tow bar wiring harness such as # HM56204 takes the separate turn signals and brake lights used by the Jeep and combines them. It also offers circuit protection so bypassing it would not be a good idea. If you want the Jeep turn signals and brake lights to be separate you would need to use the 6 diode kit # 154-792-118158.
    view full answer...

  • Recommended Best Parts for Flat Towing a 2012 Jeep Liberty
  • For your 2012 Jeep Liberty, I recommend starting with the Roadmaster EZ Base Plate Kit - Removable Arms # 521434-1 because the system is almost invisible when not in use. It will provide a solid connection to your vehicle for the Roadmaster Sterling All Terrain Tow Bar # RM-576. This tow bar will give you the safety cables and the wiring connection you need in a really nice integrated part. For your vehicle wiring I recommend the Hopkins Custom Tail Light Wiring Kit for Towed Vehicles...
    view full answer...

  • Roadmaster Base Plates for a 2012 Jeep Liberty and BlackHawk Tow Bar
  • Yes, you can use either # 521433-1 (if the Liberty does not have a rockguard or skid plate) or # 521434-1 (if it does have a rockguard or skidplate). Either set is compatible with your BlackHawk tow bar. You will also need safety cables like # RM-643. Next you will need a lighting solution. I recommend the plug and play Hopkins harness # HM56204 for the easiest installation. You will also need a supplemental braking system on the Jeep as required by law in most states. The easiest...
    view full answer...

  • Can a 2010 Jeep Liberty Renegade Be Flat-Towed
  • The 2010 Jeep Liberty could have came in either a four wheel drive or two wheel drive configuration. The four wheel drive models can be flat towed with all four wheels down whereas the two wheel drive models cannot. If you have a Renegade then you have four wheel drive so it can be flat-towed. If you take a look at page 406 of your owner's manual, this is explained for you. In order to flat tow the vehicle you are going to need a tow bar, base plate kit, safety cables, tail light wiring...
    view full answer...

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Info for this part was:

Test Fit:
Joe V
Edited by:
Leah B
Video Edited:
Zack K
Written by:
Lindsey S
Expert Research:
Michael H
Installed by:
Jeff D
Video Edited:
Joshua S
Test Fit:
Nicholas E
Updated by:
Adele M
Video by:
Andrew L
Photos by:
Jim W
Expert Research:
Jeffrey L
Updated by:
Sarah W
Updated by:
Alexander C
Photos by:
Melissa S

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