bing tracking image
  1. Accessories and Parts
  2. Roadmaster
  3. Tow Bar Wiring
  4. Extensions
  5. 7 Round - Blade to 6 Round
  6. Coiled Cord
RoadMaster 7-Wire to 4-Wire Flexo-Coil Kit

RoadMaster 7-Wire to 4-Wire Flexo-Coil Kit

Item # RM-164-7
lowest price pledge
Our Price: $76.46
You Save: 14%
Accessories and Parts
Orders above $99 qualify for Free Shipping
Shipping Weight: 2 lbs
In Stock
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

Need help with installation?
Locate installers near me
Easily and effectively connect your motor home to your towed vehicle with this water-, oil- and chemical-resistant electrical cord. Flexo-Coil technology allows cord to extend more than 8' and then contract conveniently for storage. 1-800-940-8924 to order Roadmaster accessories and parts part number RM-164-7 or order online at Free expert support on all Roadmaster products. Guaranteed Lowest Price and Fastest Shipping for RoadMaster 7-Wire to 4-Wire Flexo-Coil Kit. Accessories and Parts reviews from real customers.
  • All Info
  • Reviews (46)
  • Q & A (0)
  • Videos (2)
  • Photos
  • Why etrailer?

Roadmaster Accessories and Parts - RM-164-7

  • Tow Bar Wiring
  • Extensions
  • 7 Round - Blade to 6 Round
  • Roadmaster
  • Coiled Cord

Easily and effectively connect your motor home to your towed vehicle with this water-, oil- and chemical-resistant electrical cord. Flexo-Coil technology allows cord to extend more than 8' and then contract conveniently for storage.


  • Adapter cord can be used for multiple towing applications
    • Perfect for running power from your RV - with the 7-pole, round plug - to your towed vehicle or trailer
  • Flexo-Coil cord can expand more than 8' yet still contract to prevent dragging and tangling
  • Silicone-injected plugs prevent corrosion
  • Cord is resistant to water, oil and chemicals
  • Made in the USA

Please note: Flexo-Coil cords are not intended for use with RoadMaster All Terrain tow bars, or any other tow bar that includes cable channel guides. Only straight cords should be used with those models.

164-7 RoadMaster 7-Wire to 4-Wire Flexo-Coil Kit

Video of RoadMaster 7-Wire to 4-Wire Flexo-Coil Kit

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

Video Transcript for Roadmaster Tow Bar Wiring RM-164-7 Review

Today we're going to be reviewing part number RM-164-7. This is the RoadMaster 7-wire to 4-wire flexo-coil kit. The adapter cord can be used for multiple towing applications. It's going to be perfect for running power from your RV with the 7-way plug over to your towed vehicle or a trailer, by connecting the 4-wire plug. It's going to come with the mounting sockets. This one right here would be for the 7-way socket. It would mount through there, and it's going to allow you to connect the socket of the flexo-coil cord.

Same thing for the other side. This is going to be the socket that's going to hold your wires on your vehicle. It's going to allow you to connect our 4-wire plug directly in there. That way, you can feed power from your RV over to your towed vehicle. The flexo-coil cord can expand more than 8 feet, yet still contract to prevent dragging and tangling. It's also about making it easier for storage. As you can see here, with it fully coiled or contracted, it's only going to give us an overall length of about 15 inches.

That can be all folded up and moved to a nice stored position; whatever way you want. That's a very advantage to have for you; just a great feature to have when it comes to storage, and to prevent it from dragging once your connections are made. The plugs are going to be silicone-injected. That's designed to help prevent corrosion. The cord is going to be resistant to water, oil, and chemicals, and it's going to feature color-coded, 16-gauge inner 00:01:34 wires. Please keep in mind that the flexo-coil cords are not intended for use with RoadMaster all-terrain tow wires or any other tow wire that includes cable, channel guides. Only straight cords should be used with those models.

In the packaging, it's going to come with a nice little diagram that's going to indicate the socket pin numbers, as well as their function, on both the 7-wire and the 4-wire. That's just great to have. That's going to be found towards the back of the packaging that this system comes in. That's going to do it for our review of part number RM-164-7. This is the RoadMaster 7-wire to 4-wire flexo-coil kit. .

Customer Reviews

RoadMaster 7-Wire to 4-Wire Flexo-Coil Kit - RM-164-7

Average Customer Rating:  4.8 out of 5 stars   (46 Customer Reviews)

Easily and effectively connect your motor home to your towed vehicle with this water-, oil- and chemical-resistant electrical cord. Flexo-Coil technology allows cord to extend more than 8' and then contract conveniently for storage.


Just what I needed to replace my old cracking original cable. etrailer is always my first stop for my RV and Trailer needs.

Perfect match - replaced our original cable of 15 years.
Robert J - 11/27/2021


This Roadmaster cable is the one I needed and it is OEM so built well. My 1st one lasted 16 years, still works but showing wear finally so I decided to replace it. Good solid Roadmaster cable with every needed part for a new installation inside a strong package. I had ordered the wrong one (Blue Ox) and Etrailer made it easy to return and order the correct one. Etrailer is a pleasure to work with. This one is well built and a few dollars cheaper than the Blue Ox. I am happy!

This is working great for me! Our old cable had flat worn out so I had to replace it. I was worried about the quality since generally speaking, things are just not made as well as they were years ago. However, after a year of using this new one, it is holding up great. No problems with stretching, sagging or plugging into the receptacle on my motorhome or jeep. I am very pleased to see this!
MelMoses - 07/06/2021


I ordered this item to replace a similar harness that had been stolen out of my truck, but was very disappointed to discover that the 7-pin plug would not engage properly with the OEM receptacle on my Dodge truck with factory hitch and tow package! The spring loaded cover on the receptacle would not engage the retaining tang on the plug, and when I finally forced the plug in far enough for it to engage, the left rear turn signal and brake light on the trailer did not work. The plug on the previous harness fit perfectly, so the location of some of the 7 female slots on the Roadmaster plug was evidently not correct. I paid a premium to return it ASAP via UPS expedited shipment over the Memorial Day weekend; I eventually received a warranty replacement 17 days later. At least the 7 pin plug on replacement harness does fit correctly. I will admit that the metal 4 pin plug and receptacle on the trailer end of the Roadmaster harness are much better quality than the cheap plastic parts on the original harness. I would recommend that anyone buying one of these Roadmaster cables first check the fit of the 7 pin plug with your hitch receptacle before bothering to hook up the 4 pin receptacle for the trailer, in case you have to return it!


After having my boat trailer powder-coated blue, this was a good match for the trailer. And I like being able to disconnect the entire harness.

We sold the boat and trailer in August ‘18. The guy who bought it was impressed that I had completely rebuilt the trailer and that it had led lights and color matched cables instead of chains.
Michael - 11/13/2018


Easy ordering with customer service, and fast shipping. Thanks


I recently purchased a Blue Ox tow bar, towed vehicle brake system and three wiring harnesses for towing my Jeep Liberty with our motorhome. 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: will continue to be my first choice for RV and other related items.


This is a direct replacement part, so I'm well familiar with Roadmaster equipment. I haven't tried it yet and I don't expect any problems. The part was easy to order online and delivered when promised.

Not too well. The coil has lost its spring strength and now sags down too low. I have to wrap it around the tow bar to take up the slack.
Karl - 02/14/2020


I've only used this item for a week so I cant say if it maintains its coil. The only thing I'm not happy about is the 4 prong male / female end. It doesn't lock in good enough in my opinion. I feel with a slight tug or bouncing movement it will dislodge itself and drag on the ground. So what I do is wrap a velcro strap around it to make sure that does not happen. Should one have to do this? You decide. I did like the attach method of the wires inside the female connector. Easy and solid


I needed to order a replacement connector and a Blue Ox tow bar. The website was extremely helpful, but I had some questions and called. Kevin helped be out on the order, getting me just what I needed. I had the items before the weekend, extremely impressive!

The tow bar and electric connector are excellent products and a great way to tow my jeep behind our Nexus RV.


I am customizing my Jeep Wrangler to tow behind my motorhome. This coiled electrical plug was exactly what I ordered and needed. Excellent customer service always! I'm grateful to have etrailer to help me when I need it. I will always go to etrailer first!


Was looking for a 7 pin to 4 pin Flexo Coil Kit. Found it on line at etrailer at ma reduced price I was willing to pay. When I checked with my local RV dealer, He said I needed to buy from e trailer. Their price was below his cost..


Great website. I used e trailer once before with great results. I purchased a new RV and needed to replace a 4-WIRE to 4-WIRE cable with a 7-WIRE to 4-WIRE. GOOGLE sent me to e trailer. Their price was $25 less than three places that I visited in person, even with their shipping.


Proper product, received in good condition when I was expecting it. performed as they indicated they would. I'll certainly return to shop when necessary.


All good with the wiring harness. Exactly what I needed.


Great product but even GREATER SERVICE from eTrailer!! Thanks for the quick shipping & telephone assistance !


This part solved my problem and after simply plugging the cable in, all lights worked perfectly. Thanks for the prompt shipping and delivery, it arrived in time for our holiday travels.


Very knowledgeable people to work with. Great products at the best prices. Every order I've placed has always been correct with no issues. You guy's ROCK. LARRY


Hopefully its excellant, I havent tryed it yet, but im sure its fine!
I will shop here for more of my rv parts.
the prices are very reasonable compared to CW!


You guys are the best! Great products, competitive price and super customer service. I have never been disappointed by etrailer....ever!


Product looks to be of good quality although I have not installed it as of this writing. Shipping was very fast and materials packaged securely.


The products are excellent, but the shipping could be faster.


Just what I ordered; fast response. Enjoyed doing business with you!


Arrived on time, perfect condition too. The whole kit was perfect for my application.


This product meet my expectations on price and quality. Thanks to customer service for helping me find it


Hooks up fast and has weathered well the first year.

Show More Reviews

Ask the Experts about this Roadmaster Accessories and Parts

  • Do Connectors Come Already Wired to Harness on RoadMaster 7- to 4-Wire Flexo-Coil Kit # RM-164-7
    Yes, the RoadMaster 7-Wire to 4-Wire Flexo-Coil Kit # RM-164-7 does come with the connectors already attached to the wiring harness. No need to have to wire into the connectors yourself. I have included a link to a video review for you.
    view full answer...
  • Wiring Extension for Use with a Roadmaster Sterling Tow Bar
    For your Sterling tow bar I recommend Roadmaster extension # RM-98164-7. It is a straight cable with the 4-Way unattached so you can route the wire through the guides on the Sterling tow bar. With an extension like # RM-164-7 you would need to wrap it around the tow bar arm instead of using the guide channels on the Sterling tow bar.
    view full answer...
  • How Long is the RoadMaster 7-Wire to 4-Wire Straight Cord Kit # RM-98164-7
    I spoke to my contact at Roadmaster who told me that the 7-Wire to 4-Wire straight cord kit, # RM-98164-7, is 6-1/2 feet or 78 inches long. If you need even more length I recommend the Flexo-Coil kit, # RM-164-7 which is 8 feet or 96 inches long when stretched out.
    view full answer...
  • Wiring my 1997 Jeep Wrangler lights to work off my motorhome wiring
    Your Jeep does not have turn signal lights separate from the brake lights so you will not need the RM-732, Roadmaster Brite-Lite Wiring Converter. Your RV already has the 4 and 7 pole connectors wired so the RV already has a converter if it was needed to install the trailer wiring so your wiring to the Jeep should be very straight forward. I have posted a link to our wiring page and to our tow-bar electrical page for you. You may want to consider a Roadmaster 7-Wire to 4-Wire Flexo-Coil...
    view full answer...
  • Is 10 Ft Flex Coil 7-Way Round To 4-Way Flat Adapter Cord Available
    The closest to a 10 ft coiled 4-way to 7-way round adapter cord we carry is the 8 ft long RoadMaster 7-Wire to 4-Wire Flexo-Coil Kit, part # RM-164-7. This water, oil, and chemical-resistant cord can extend to more than 8 ft and then conveniently contract for easy storage. We do not offer any 4-way to 7-way adapter coiled cords that are 10 ft long or longer. Please note that Flexo-Coil cords are not intended for use with RoadMaster All Terrain tow bars, or any other tow bar that includes...
    view full answer...
  • 7-Wire to 4-Wire Umbilical for Flat Towing With Roadmaster Falcon All-Terrain Tow Bar
    We've got just the thing. If you prefer a coiled 7 wire to 4 wire cord, use # RM-164-7 or # RM-98164-7 for the straight cable. If you have the # RM-522 Falcon All Terrain tow bar, the # RM-98164-7 straight cable is designed to fit into the cable guides on the tow bar.
    view full answer...
  • Can the Roadmaster Diode 7-Wire to 4-Wire Flexo-Coil Wiring Kit Be Purchased Without the Diodes
    Yes, we do offer the Roadmaster Diode 7-Wire to 4-Wire Flexo-Coil Wiring Kit part # RM-15247 without the diodes and bonded four wire harness. In order to obtain this you'll need the RoadMaster 7-Wire to 4-Wire Flexo-Coil Kit part # RM-164-7.
    view full answer...
  • Do the Turn/Brake Signals on the Wiring Kit # BX88267 Need to be Separated for a 2004 Mini Cooper
    I am a little bit confused as to what you are wanting to do. The Blue Ox Tail Light Wiring Kit # BX88267 that you mentioned uses its own bulb that works both as the brake and turning signals. It completely bypasses the wiring on your 2004 Mini Cooper and directly connects to the motorhome for signal source. If you check out the linked installation video you can see our team install this kit as well as the Flexo-Coil Kit # RM-164-7 for flat towed wiring.
    view full answer...
  • Converting 7-Way on Motorhome to Roadmaster Diode Kit 4-Pole on Flat Towed 2012 Ford F150
    To convert the 7-way on your motorhome to work with the 4-pole plug of the Roadmaster Diode Kit you referenced, you have a couple of options. You could use an adapter like # PK12716 that would plug into the 7-way on your motorhome. You could then plug the umbilical from the towed vehicle into the adapter. This would be a good option if you were not planning on towing frequently. Another option would be to remove the 4-pole flat connector on the truck, and replace it with a 4-pin round...
    view full answer...
  • Availability of Coiled 4-Way to 7-Way Cable for Flat Towing
    Just the coiled cable from the Roadmaster Flexo-Coil Wiring Kit # RM-15247 is found as part # RM-164-7 on our site. Pretty much all of the "cable only" kits come with the socket and bracket for the towed vehicle side like what you see with this kit. For something a little more cost-effective I recommend going with the Hopkins Nite-Glow # HM47044 instead. This is the exact same thing just from Hopkins instead of Roadmaster. Hopkins is one of the leading wiring manufacturers on the market...
    view full answer...
  • Roadmaster InvisiBrake # RM-8700 Used w/ TrailerMate Wiring # TM781124 on 2015 Wrangler Unlimited
    Yes, the Roadmaster InvisiBrake Supplemental Braking System, # RM-8700, on 2015 Jeep Wrangler Unlimited. You will need the Hopkins Tail Light Wiring Kit, # HM56200. This harness would not require the use of diodes when using the InvisiBrake system. As for a coiled 7-way, I recommend going with the RoadMaster 7-Wire to 4-Wire Flexo-Coil Kit, # RM-164-7. For this you would just cut off the 4-way flat connector to be able to wire the new 4-way round connector and you are ready to go.
    view full answer...
  • Additional Wiring Parts Needed to Flat Tow a 2012 Jeep Liberty Behind a RV
    Once you install the Roadmaster Bulb and Socket Wiring Kit, # RM-155, on your 2012 Jeep Liberty, you will want to determine what type of trailer connector socket is on your RV. If your RV has a 4-way flat connector, then you can install a 4-way trailer end connector like part # 18004. If your RV has a 7-way connector, then you could install a 7-way to 4-way wiring kit like part # RM-164-7. This allows you to install a 4-way socket on your Jeep and includes a Flexo-Coil cord to connect...
    view full answer...
  • Flat Tow Wiring Kit For 2022 Chevy Tahoe Premier
    There is a flat tow wiring kit for your 2022 Chevy Tahoe Premier (which is what I think you meant as there isn't a Premium), but the Hopkins # HM56115 does not fit the Premier models. Your '22 Tahoe has variable voltage taillights, which means multiple electrical signals are on a single wire, so it needs a specific wiring kit: - Roadmaster Universal Wiring Kit with Smart Diodes for Variable Voltage Incandescent Tail Lights # RO94FR The # RO94FR moderates the voltage correctly so that...
    view full answer...
  • Flat Towing Wiring Harness Options for 2012 Fiat 500
    There are two ways you could wire your Fiat 500 for flat towing. In scenario # 1, you could use a 4 diode kit like # RM-15247 which would use your tail lights as stop/turn/brake lamps. Your lights would work normally when actually driving the Fiat, but when you're flat towing, you'd only use the red bulb on the back of the Fiat for all the taillight functions. Scenario # 2, if you wanted the taillights on the Fiat to operate 'normally', that is to have the turn signals use the amber bulb...
    view full answer...
  • Adapting Roadmaster Blackhawk Tow Bar to Blue Ox Base Plates for Flat Towing 2016 Jeep Cherokee
    I'm not certain which adapter you used, but the # RM-031 adapter would install at the end of the tow bar arms and allow you to attach to the Blue Ox base plate on your Jeep Cherokee. To complete your towing system, you'll need safety cables like # RM-643, a wiring harness like part # RM-154, a wiring umbilical like part # RM-164-7 and a supplemental braking system like the Delta Force part # SM99242. The Delta Force is a portable unit that will take only moments to install and remove. When...
    view full answer...
  • Wiring Extension for Flat Towing a Vehicle Behind Monaco RV with 7-Way Trailer Connector
    In order to determine the proper set up for your new towed vehicle (called a toad; the vehicle you will be flat towing behind the motor home) I would need to know the year, make, and model of that vehicle. Most of the tow bar wiring uses a 4-Way flat trailer connector with a few exceptions. Since your RV has a 7-Way trailer connector ideally you would use a cable that has a 7-Way on one end to plug into the RV and a matching connector on the other end for the tow bar wiring/lighting system...
    view full answer...
  • How to Determine if Used Roadmaster Falcon 2 Tow Bar is Complete
    The # RM-521445-5 base plates install to the front frame structure of the vehicle. The crossbar you speak of that came with your # RM-520 falcon tow bar consists of a crossbar for stability and a quick disconnect that allows the tow bar to be quickly disconnected from the vehicle just by pulling two linchpins. To be sure you have all the necessary parts, take a quick look at the instructions for the Falcon 2 Tow Bar that I've linked for you. Looking over the instructions will easily help...
    view full answer...
  • What Equipment is Needed to Flat Tow 2004 Jeep Grand Cherokee
    To flat tow your 2004 Jeep Grand Cherokee, you will need a base plate kit, a tow bar, safety cables, towed vehicle wiring, and a supplemental braking system. It is also likely that you will need a wiring extension to connect the RV's wiring with the Grand Cherokee's and a high-low adapter that will allow you to have the tow bar level while towing your vehicle. Since you are looking at the previous generation of the Roadmaster Falcon Tow Bar # RM-520, it will be easiest to connect the tow...
    view full answer...
  • Flat Towing Setup Recommendation for a 2014 Honda CR-V
    We have everything you would need to flat tow your 2014 Honda CR-V. First lets start with a base plate kit as that is the attachment point on the vehicle. For that you would want the Blue Ox Base Plate kit part # BX2258. I attached an install video for you to check out as well. The Blue Ox Alpha # BX7380 is the most popular tow bar we offer that has been confirmed to work with the base plate kit so it should work very well. It also comes with safety cables. For trailer wiring you would...
    view full answer...
  • Parts Needed to Flat Tow 2014 Honda CR-V
    Sounds like you are referring to flat tow products for a 2014 Honda CR-V which first starts with a base plate kit. For that you would want the Blue Ox Base Plate kit part # BX2258. I attached an install video for you to check out as well. The Blue Ox Alpha # BX7380 is the most popular tow bar we offer that has been confirmed to work with the base plate kit so it should work very well. It also comes with safety cables. For trailer wiring you would want the Hopkins Kit part # HM56304...
    view full answer...
  • What Would I Need to Flat Tow my 2005 Chevy Aveo
    I did some checking and it looks like manual transmission 2005 Chevy Aveos can be flat towed without issue, but the automatic transmission Aveos can not be flat towed. You would have to check your owners manual to see if a tow dolly like a RoadMaster Tow Dolly with Electric Brakes, part # RM-2000-1 could be used. I attached installation instructions below for you to check out also. If you had a manual transmission you could use a RoadMaster Tracker Tow Bar - 5,000 lbs, part # RM-020, like...
    view full answer...
  • How to Change Out 4-Way at Rear of Motorhome to Work with 7-Way on Trailer
    Thank you for the pictures! What you may be able to do is install the Hopkins # HM47210 on your motorhome to replace your current 4-Way round connector. I'm guessing the 2 wires for your brake controller system are for 12V power and for the brake controller signal. If this is the case then you will need to connect the following functions on your motorhome wiring with the following wires from the Hopkins connector: White - Ground Yellow - Left Stop/Turn Green - Right Stop/Turn Brown -...
    view full answer...
    Image 1 for Image 2 for Image 3 for Image 4 for
  • Parts Needed to Flat Towing 2014 Honda CR-V
    You are correct with the parts you listed. I double checked for you, the Blue Ox Base Plates # BX2258, Blue Ox Alpha Tow Bar # BX7380, Hopkins Tow Bar Wiring # HM56304, Roadmaster InvisiBrake Supplemental Braking System # RM-8700 , Roadmaster Brake-Lite Relay # RM-88400, Roadmaster FuseMaster Fuse Bypass # RM76511, and Roadmaster 7-way to 4-way Extention # RM-164-7 will all fit and will be needed to flat tow your 2014 Honda CR-V. The Blue Ox Base Plate and Receiver Lock Kit # BX88177 is...
    view full answer...

Do you have a question about this Accessories and Part?

  • Why

    At we guarantee:
  • Highest quality accessories and parts for the best price.

    Our Lowest Price Pledge ensures you will never overpay for the parts you need.
  • Real product know-how.

    We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.
  • Most detailed, accurate accessories and part information available.

    Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.
  • Installations, made easy.

    We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.
  • Fast shipping.

    Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.
  • Personalized service for life.

    We provide one-on-one, personalized service from the ordering process through the life of your product.
  • Trusted since 1946.

    We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.
  • Returns Policy

    Need to return an item? No problem. Please read our Returns Policy for more information.

Info for this part was:

Employee Zack K
Video Edited:
Zack K
Employee Michael H
Expert Research:
Michael H
Employee Cole B
Installed by:
Cole B

At we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.