1. Tow Bar Wiring
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Hopkins Custom Tail Light Wiring Kit for Towed Vehicles

Hopkins Custom Tail Light Wiring Kit for Towed Vehicles

Item # HM56100
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Tow Bar Wiring

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Hopkins Plugs into Vehicle Wiring - HM56100
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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. Lowest Prices for the best tow bar wiring from Hopkins. Hopkins Custom Tail Light Wiring Kit for Towed Vehicles part number HM56100 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
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  • Reviews (14)
  • Q & A (15)
  • Videos (2)
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  • Why etrailer?

Hopkins Tow Bar Wiring - HM56100

  • 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.


  • Lets you wire your vehicle to accept your RV's tail, brake, and turn signal lights for flat towing
    • 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.

Do You Need a Brake Light Relay?

Because your vehicle has a combined lighting system - wherein the brake signals and the turn signals are carried on a single wire - 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.

11156100 Hopkins Plug-In Simple Dinghy Towing Harness

Replaces 56100

This Product Fits The Following Vehicles

California residents: click here

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 Tail Light Wiring Kit Installation - 2008 Chevrolet HHR

Today, on our 2008 Chevrolet HHR we're going to be installing the Hopkins tow bar wiring, part number HM56100. To begin our install, we're going to start at the rear of the vehicle. We need to open up the rear hatch and remove the access panels just behind the tail light assemblies. There's one on each side. I'm just going to use a flat blade screw driver, get behind it and pop it free. Behind the access panel, we can see the manufacturer's wiring as it comes into the tail light. Here from the converter box is our yellow wire connector that will ultimately plug in here behind the driver's side tail light assembly.

Before I make any connections, we're going to go ahead and remove the rear cargo cover, go ahead and remove the mat, rear cargo compartment or storage then our spare tire cover and then the rear threshold. Now to remove the rear threshold, we'll simply just get underneath and work it up releasing the fasteners underneath. Once we turn it over, you can see the fasteners that we're securing it, and I'll set that aside. This will allow us access underneath the paneling and ultimately to the manufacturer's wiring on both sides. Now, starting here on the passenger's side, I'm going to go ahead and remove the manufacturer's connector from the back of the tail light socket. To do that, we'll put back on the locking tab and just work the connector off of the socket. Now, once it's disconnected, we'll bring in the green wire connector that comes from the converter box of our new towed vehicle harness.

We're going to feed it underneath the paneling and up behind the tail light. Then we can take the manufacturer's wiring that we just disconnected from the tail light socket, plug it into the new wiring harness and the other set of the harness will plug into the tail light socket. Just like that, we've connected the passenger's side, and we can move over to the driver's side and repeat the same process with the yellow wire connector. Next, I'll go ahead and secure the wiring as necessary using the zip ties provided with the install kit. Now, with our wiring connected behind the tail light assemblies, we need to route our fourfold connector three-wire harness up to the front of the vehicle. To do that, you could either run it inside, underneath the paneling, ultimately through the firewall and up to the base plate or underneath the vehicle and up to the base plate. Either way we'll have to either, one, have a hole large enough to pass the fourfold connector through, or, two, cut the wire, so that you can pass the wire through and then repair it.

To route it outside the vehicle, we're going to pass through the manufacturer's grommet here underneath the threshold. To do that, I'm going to go ahead and pull the grommet out and just use a pair of side cutters or snips to cut a small slice into the grommet that'll be large enough that we can pass the wire through. Now we'll go ahead and cut the four-pole end off. Note, we'll go ahead and save the white wire so that we can re-attach it to the new connector that'll be at the front of the vehicle and which will ultimately be the ground for our electrical circuit. Now, with the hole cut in the grommet, let's go ahead and push our wires through it. I'm just going to go ahead and get it started then push the wiring through the hole which will ultimately route underneath the vehicle, and then we can reinstall the grommet. Next, I'll move underneath the vehicle and pull the rest of my three-wire harness underneath the vehicle and start routing it up to the front.

Now, if you run into an area where you don't have anything to zip tie to, you can use one of the Redline metal loom clamps, part number A0250 and a self-tapping screw and create attachment point. Keep in mind when routing any of your wiring, stay away from moving opponents just steering your suspension or excessive heat such as exhaust. We'll use the zip tie provided to secure it as necessary. Now, we went ahead and followed the firewall up to the top of the engine compartment, manufacturer's wiring across the driver's side, in the fender well and then came back down the driver's side core support and routed over to the center of the vehicle and ultimately to the base plate wiring attachment point. Now, that we've got our lighting circuit wiring run here to the front, there are varying options available. For our application, we're going to be installing a six pin round connector. We'll use the three wires that we ran for our electrical circuit, the white wire, which is our ground with the pre-install ring terminal and then the additional wires for a breaking system that's already been pre-installed. Once we have all our wires run into the new connector, we'll then mount that connector to the base plate. With that, this will complete the install of the Hopkins tow bar wiring, part number HM56100, on our 2008 Chevrolet HHR. .

Customer Reviews

Hopkins Custom Tail Light Wiring Kit for Towed Vehicles - HM56100

Average Customer Rating:  4.4 out of 5 stars   (14 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.

- HM56100

Harness did not work on the driver's side. The good news is Etrailer customer support is shipping me a replacement. Sometimes things don't work, but a good customer service overtakes that. 327984

- HM56100

It works great 638823

- HM56100
2008 Chevrolet HHR

The wiring kit was very easy to install and the instructions were very helpful. Works just like it should. 608072

- HM56100

Thank you. 575685

- HM56100

Everything as ordered would buy again 547152

- HM56100
2007 Chevrolet HHR

Product was wadded up in a small box with no instructions. Looked used. The last one I purchased was in a nice blister pack. If I Hadn't already done an install on my friends HHR I would have needed the instructions. I'm sure this was a fluke. I've never had a problem with their products in the past and I will purchase again. It works just as it should. 375074

Thanks for leaving a review Captain Ron. This should have come to you in a blister pack. I apologize for the mistake and suggest that if this ever happens again that you call customer service and they will resolve this problem.
Hopkins C from - 05/03/2017


- HM56100
2008 Chevrolet HHR

had good experience with the wiring kit. everything connected perfectly and worked as designed. good product. 371857

Thanks for taking the time to write a review and rate the HM56100 wiring kit, Wilson !!! We are pleased that it met your wiring needs.
Hopkins C from - 04/26/2017


- HM56100
2007 Chevrolet HHR

Tow wire kit HM56100 was a direct fit for my 2007 Chevy HHR which will be flat towed behind my motor home. Shipment was delivered on time. etrailer is a great company to do business with. 359378

- HM56100

Fantastic unit. Easy to install and makes for a professional look. 317672

- HM56100
2007 Chevrolet HHR

Quick shipping and communications. Easy to install 284841

- HM56100

I was very happy to see the wiring kit on etrailer.com webpage. It couldn't be any simpler to place my order and then have it in my hand in 2 1/2 days. Installation could not have been any easier with the direction that came with the kit. I have to say etrailer ranks in my top companies to buy from on the internet. Thanks etrailer. 254046

I have not had any problems with the product. I love things that work as it should.
Robert S - 05/30/2017


- HM56100
2006 Chevrolet HHR

received harness on Tuesday the 4th, installed it on Wed. took about an hour. hardest part is running wires to front of car., but that part would be difficult with any product.. 216892

- HM56100
2007 Chevy HHR

the product i bought kooks great I have the wiring set up for a 2007 hhrI received the package wensday 5/15/15 . it took 3 hrs to put every thing to gather , your inst. was a great help. thanks i will with out a doubt use your co more. robert rasmussen sorry no pics. 212015

Does your license plate lights work?
-- comment by: Phil - 02/15/2016


- HM56100
2007 Chevrolet Cobalt

Easy to hook up and install the wiring. Ran mine inside the car behind the molding on the floor below the door and through the firewall. 168363


Ask the Experts about this Hopkins Tow Bar Wiring

  • Compatibility of Hopkins Towing Wiring Harness HM56100 with Brake Buddy Braking System
    The built-on diodes on your Hopkins # HM56100 will work just fine. We've found that this harness isn't compatible with some braking systems, but your Brake Buddy is of the type that is compatible. Everything will work together well. I'll link you to some FAQ articles that I hope you'll find helpful.
    view full answer...
  • Running Lights on 2005 Toyota Avalon Not Working After Installing Trailer Wiring Harness # HM56100
    The wiring harness that you referenced, Hopkins # HM56100, is not intended for use with a trailer. This harness is designed to operate the 2005 Toyota Avalon lights in flat-towing applications when using a tow bar behind a motor home. The correct trailer wiring harness for your car is Curt # C59236 which is a hard-wired installation that provides a flat-4-pole trailer connector to power your trailer lights. Written installation instructions as well as a video are linked at right.
    view full answer...
  • How Does the Hopkins Custom Tail Light Wiring Kit # HM56100 Install on a Vehicle
    To answer your question simply, yes. The Hopkins Custom Tail Light Wiring Kit # HM56100 plugs in line with the taillight wiring harness of your 2007 Chevy Cobalt. You will unplug your taillight harness on your vehicle and then plug it into the corresponding connector of the # HM56100. The other connector of the # HM56100 will then plug into the connector for the vehicle's wiring and the install will be complete. When you are flat towing this vehicle you will plug the 4-way of this...
    view full answer...
  • Plug-In Tow Bar Wiring for a 2007 Chevy HHR
    The connectors that plug into the tail light wiring in Hopkins tow bar wiring kit # HM56100 for the 2007 Chevy HHR are not available by themselves. You would need the whole kit. Consult your owners manual because it also looks like you will need to pull a fuse to flat tow your HHR. To make this process as easy as flipping a switch you can use fuse bypass # RM76511.
    view full answer...
  • How To Flat-Tow a Chevrolet HHR SS
    Yes, the Chevrolet HHR SS is flat-towable with all four wheels down. In order to do so you are going to need a tow bar, base plate kit, safety cables, tail light wiring harness, supplemental braking system, and possibly a high-low adapter. There may also be a few other smaller components that are needed depending on options the vehicle is equipped with. For a tow bar, I recommend the Roadmaster Falcon 2 Tow Bar part # RM-520. The Falcon is one very nice tow bar. It has a non-binding...
    view full answer...
  • Parts Needed to Flat Tow 2007 Chevy HHR
    We have everything you need to flat tow your 2007 Chevy HHR. The first thing you'll need is a base plate kit. This is what provides the connection point for the tow bar to the vehicle frame. For that we have the Roadmaster kit part # 3141-1 which is a confirmed fit. Next you'll need a tow bar. For that we have the Roadmaster Sterling # RM-576 which is very easy to use and comes with safety cables and wiring to go from the rear of the tow vehicle to the front of your HHR. For a tow bar cover...
    view full answer...
  • Parts Needed to Flat Tow a 2009 Chevy HHR Behind a Motor Home
    This has actually come up before and Roadmaster explained that they have not tested their base plates with the EAZ Lift tow bars so I cannot say if they will fit or not. You would need to contact EAZ Lift to determine if they have tested it with Roadmaster or Blue Ox base plates. What I recommend is using the Roadmaster base plates, # 3141-1, and using a tow bar that you know is compatible like the Falcon 2, # RM-520. You will also need safety cables like # RM-643. Next you will need...
    view full answer...
  • How to Use the Lights of My 2006 Chevrolet HHR on a Tow Dolly Behind an RV
    It sounds like you want to use the lights on your 2006 Chevrolet HHR instead of the lights on your tow dolly when towing your vehicle. If this is the case, you will need the Hopkins Tail Light Custom Wiring Kit # HM56100. This will allow you to connect the HHR directly to your motorhome and power the lights instead of the dolly. The Curt T-Connector Wiring Harness # C55432 you asked about is what you would use if you were towing a trailer with the HHR. I've attached a video showing...
    view full answer...
  • Parts Needed to Flat Tow a 2007 Chevy HHR Behind a Motor Home
    I looked up an online version of the owners manual for a 2007 Chevy HHR and found that it can be flat towed. It gives the following steps: First set the parking brake. Then turn the ignition key to ACC to unlock the steering wheel. Next shift into neutral. Then release the parking brake. You also have to pull fuse 8 from the floor console fuse block to prevent draining the battery. The manual also states to not exceed 65 miles per hour. Any time you ever have a flat towing question, you...
    view full answer...
  • How to Flat Tow a 2007 Chevy HHR Behind a Motor Home with a Blue Ox Aventa Tow Bar
    Yes, the Aventa tow bar is compatible with the Blue Ox base plates # BX1692 on your Chevy HHR. In addition to the tow bar and base plates, you will need safety cables, # BX88196, if you do not already have some. For lighting you can use a simple magnetic kit such as # C-ATL20A. Or you can use a kit that plugs in line with the vehicle tail light wiring, # HM56100. It looks like you will need to pull fuses to flat tow your HHR. Check the owners manual to confirm. To make this process...
    view full answer...
  • Recommended Parts for Flat Dinghy/Recreational Towing a 2008-2010 Chevy HHR
    To flat tow your 2008-2010 Chevy HHR you will need a base plate kit, tow bar, safety cables, vehicle tow bar wiring, a supplemental braking system, and most likely a high-low adapter. For base plates I recommend going with either Roadmaster part # 3141-1 for a Standard model or part # 523159-1 if you have an SS model. The tow bar I recommend for either of these kits is the Roadmaster Sterling All Terrain # RM-576. This is rated for 8,000 lbs and comes with safety cables that are rated...
    view full answer...
  • Base Plate Kit and Flat Towing Accessories for 2006 Cheverolet HHR
    An HHR LS and LT use the same base plate kit. As long as the HHR is NOT an SS model, the Roadmaster # 3141-1 base plate kit you referenced would work just find for you. To flat tow your vehicle, you'll also need to check with your owner's manual and determine if your HHR is capable of being flat towed. To complete your towing system, you'll need a towbar, safety cables, wiring, and a supplemental braking system. For a towbar, the Roadmaster Falcon 2, part # RM-520 would be a great...
    view full answer...
  • Parts Needed To Use Roadmaster Sterling Tow Bar To Flat Tow 2007 Chevy HHR
    I can help you get the parts you need to flat tow the 2007 Chevy HHR with the Roadmaster Sterling All Terrain tow bar part # RM-576. I recommend the Roadmaster Base Plate kit part # 3141-1 to fit the Sterling Tow Bar. For the wiring I recommend Hopkins part # HM56100. It wires the towed vehicle to accept the RV's tail, brake and turn signals when flat towing without splicing into your vehicle's wiring. According to Roadmaster there are fuses that need to be pulled in the HHR when...
    view full answer...
  • Recommended Flat Towing System Parts for 2007 Chevy HHR
    To flat tow your 2007 Chevy HHR there are a few components you will need that all work together to give you a safe towing experience. I recommend starting with the Roadmaster XL Base Plate Kit - Removable Arms # 3141-1 and using Loctite Threadlocker # LT37420 to secure the hardware when installing. Then for your tow bar I recommend the Roadmaster Sterling All Terrain, Non-Binding Tow Bar # RM-576 which has integrated safety cables and a wiring connector to connect your motorhome to...
    view full answer...
  • Tail Light Wiring Kit to Tow a 2007 Chevrolet HHR Behind a Class A Coach
    The Roadmaster Universal Hy-Power Diode Wiring Kit, # RM-154, will work with your 2007 Chevrolet HHR. I have attached an installation video of this kit on a 2011 HHR for you to check out. If you do not want to cut your vehicles tail light wiring, then you may be interested in the Hopkins Custom Tail Light Wiring Kit for Towed Vehicles, # HM56100. I prefer this wiring harness because it has a simple plug-in installation. I have attached a few help articles on tow bar wiring for you to...
    view full answer...

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Info for this part was:

Edited by:
Leah B
Written by:
Lindsey S
Expert Research:
Michael H
Installed by:
Jeff D
Updated by:
Sarah W
Updated by:
Alexander C

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