bing tracking image
  1. Flat Tow Wiring Harness
  2. Roadmaster
  3. Adapters
  4. Extension Cord
  5. Plugs into Vehicle Wiring
  6. 4 Flat
Roadmaster Extension Loop for Towed Vehicles - Dual 4-Way Flat Trailer Ends - 6' Long
etrailer Installation
We'll connect you with nearby partnered installers who know this exact setup.
Roadmaster

Roadmaster Extension Loop for Towed Vehicles - Dual 4-Way Flat Trailer Ends - 6' Long

Part Number: RM-300150-00
In Stock
$38.96
Retail:$40.92
You Save: 5%
Flat Tow Wiring Harness
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.
By submitting this form, you understand and agree to our Terms of Sale, Website Terms of Use and Privacy Policy.

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

Customer Photos

Videos

etrailer Installation
We'll connect you with nearby partnered installers who know this exact setup.
Extension wiring loop with 2 trailer ends lets you connect your RV and towed vehicle. Each male end easily plugs into a 4-way flat, vehicle-end plug. 1-800-940-8924 to order Roadmaster flat tow wiring harness part number RM-300150-00 or order online at etrailer.com. Free expert support on all Roadmaster products. Great prices and Fastest Shipping for Roadmaster Extension Loop for Towed Vehicles - Dual 4-Way Flat Trailer Ends - 6' Long. Flat Tow Wiring Harness reviews from real customers.
  • All Info
  • Reviews (44)
  • Q & A (0)
  • Videos (1)
  • Photos

Roadmaster Flat Tow Wiring Harness - RM-300150-00

  • Adapters
  • Extension Cord
  • Plugs into Vehicle Wiring
  • 4 Flat
  • Roadmaster
  • Universal Fit

Extension wiring loop with 2 trailer ends lets you connect your RV and towed vehicle. Each male end easily plugs into a 4-way flat, vehicle-end plug.


Features:

  • Wiring loop lets you connect your RV to your towed vehicle
  • Dual trailer (male) ends plug into 4-way flat vehicle ends
  • 6' Long


300150-00 Road Master Extension Loop for Towed Vehicles - 2 4Way Flat Trailer Ends - 72" Long

Compare to Hopkins HM48235





Video of Roadmaster Extension Loop for Towed Vehicles - Dual 4-Way Flat Trailer Ends - 6' Long
Video Thumbnail Video Player Dialog

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




Video Transcript for Roadmaster Extension Loop for Towed Vehicles Feature Review

Today we're going to be taking a look at the Roadmaster Extension Loop for towed vehicles. This wiring loop lets you connect your RV to your towed vehicle. It's going to feature the dual trailer male-end plugs that would simply plug into a four-way flat vehicle end connector. This loop has a measurement length of 6 feet long, and each connector is going to come with a dust cap. That's going to do it for today's look at the Roadmaster Extension Loop for towed vehicles.

Customer Satisfaction Score:

Ratings & Reviews

4.9

44 reviews
5 Stars
(42)
4 Stars
(1)
3 Stars
(1)
2 Stars
(0)
1 Star
(0)
Review Sort Icon
by:
fast shipping
by:
Thank you... Extra length of the wire and dual male ends was exactly what was needed.
by:
Arrived quickly and is the exact item I needed! Fairly priced shipping and merchandise!
by:
I had installed the ROADMASTER tail light wiring kit on my towed Jeep which included this jumper cable to connect the car to my RV. Somehow it dragged on the ground while towing and wore through some insulation and one wire. I was very glad to see I could order just this jumper cable to make my install as good as new. ROADMASTER helped me identify the part number and etrailer stocked them at a good price.
Brad profile picture

Brad

6/16/2018

Its been a year, and everything is still working great. I am more careful how I support this jumper now.

by:
Hard to find item and at a great price point! I use it to connect my 90 Suzuki to my 2009 Explorer when I tow it to the beach!
by:
My review is based primarily on the service I received when calling etrailer.com. I cannot brag enough on how friendly, helpful, and efficient the representative was on the phone. I needed to purchase this product as a replacement for a component which came in a larger package/bundle I had previously purchased. I described the individual item I needed, and she directed me right to it and completed my order then and there, saving me the much larger sum of money which would have been required to purchase the entire package all over again. It was so easy. I'm very impressed with not only the inventory and products, but perhaps even more so the staff and service of this great company. I highly recommend them.
by:
We ordered tow mounts, road master tow bar and some accessories from etrailer for a 2009 Suburban. All the items arrived within a few days and packed in secure boxes. After just a little drilling the mounts went right on, the instructions are very detailed and easy to follow. I highly recommend etrailer.com for your towing needs.
by:
Nice product, hard to find elsewhere too. Thank you
by:
First time buying a tow bar. Great experience with Jesse at errailer. etrailer videos are excellent.
by:
Easy to install and needed for extending the wiring for the tow hitch.
by:
Needed make to make extension for trailer lights. Which is not easy to find. Thanks to etrailer.com, I got what I needed. Easy to order on site. Delivered in a timely manner. No complaints from here!
by:
Crazy expensive for 6’ of wire. Unbelievably, no one else sells the same piece of wire?!??!
Dave T. profile picture

Dave T.

2/8/2025

Keeps on working as expected-still the most expensive piece of wire I’ve ever bought for its size and makeup. I’ll be building my own of this ever gives up!

by:
Product was just as described and met my needs perfectly. Needed a replacement quickly for a planned trip and item came on time as promised.
by:
Nice and small, bunches better than the coiled cable I had before.
by:
Perfect! Hard to find this cable in local stores and etrailer not only had it, but at a great price.
by:
Exactly what I needed for towing my Jeep. Arrived quickly. The pigtail currently on there was too short.
by:
Fast Shipping. Product as described.
by:
Checked with several RV shops, marine stores, and a place that sells trailers. The trailer placed rigged up a cable for $30. Spent more than a few hours scouring the web till I found etrailer.com and not sure of the nomenclature of what I needed, emailed their customer service with a description of the application and sent a picture of the connectors and within a couple days was sent the pic of this product. I was apprehensive at first until I viewed all the pictures then I was sold and immediately placed my order. Received the product 2 days ahead of the predicted arrival date and couldn't be happier. Highly recommend etrailer.com. I have actually bookmarked the site for later reference.
by:
Just what I needed and ordered
Love this company and the quality of service and product I receive
Would and have recommended this site to others
Will be back shopping soon have another project in the works
by:
Purchased this as a backup for the one I purchased earlier. The one that was replaced had gotten nicked when folding or tow bar.
by:
perfect for flat tow vehicle
by:
Great service, great price.
Thanks.
by:
Products were delivered promptly and were exactly what I ordered. I would not hesitate using this site again. Great service.
by:
Good quality. Fair price. Timely delivery.
by:
Chelsea was an amazing product specialist! Knowledgeable and professional.
25
44
true
Show More Reviews

See what our Experts say about this Roadmaster Flat Tow Wiring Harness

  • Is There Jacketed Dual Male 4-Way Extension
    Hi Derek, There is not another version of the Roadmaster Extension Loop for Towed Vehicles - Dual 4-Way Flat Trailer Ends # RM-300150-00 that is jacketed or has a more robust design. That said, I honestly wouldn't worry about this extension being damaged or unable to hold up. It's the same wire cover used on standard vehicle 4-ways and won't be damaged during any type of regular towing.
    view full answer...
  • License Plate Mounting Bracket Solution for Ladder on Class B Motorhome
    Thank you for all of the details and photos! For your application I recommend using the Thule License Plate Holder for Bike Racks # TH35JV along with the 6' Long Roadmaster Extension Loop # RM-300150-00. This gives you exactly what you're needing and eliminates the need to hardwire connections like you'd need to do with the LED Bracket # 328-003-70BE or Optronics # LPL55CB. The Thule bracket also comes with straps to mount it so you can wrap those around your ladder rungs which will not...
    view full answer...
    Image 1 for Image 2 for
  • Need 4-Pole Flat Male to 4-Pole Flat Male Wiring Harness Adapter
    We do have exactly what you need to join two female (vehicle-side) 4-pole flat trailer connectors. Roadmaster offers their # RM-300150-00 extension wiring loop which has male (trailer side) connectors on both ends of a 6-foot harness. This will allow you to join the two female 4-pole connectors on the truck and trailer.
    view full answer...
  • Trailer Connector With 4-Way Male Connector On Both Ends
    We have a dual 4-way harness that has the trailer side adapter on each end that may work for you. It is part # RM-300150-00. This adapter is 6-ft long. We do not have a rigid adapter with a male connector on both ends.
    view full answer...
  • Dual 4-Way Flat Connector Adapter With Two Male Ends for Flat Towing
    We have the exact part you need with the Roadmaster Extension Loop for Towed Vehicles - Dual 4-Way Flat Trailer Ends # RM-300150-00. This has two male connectors for you to plug into the harness on your Jeep Wrangler and on your RV. I have added a link to a video review of this adapter to check out as well.
    view full answer...
  • Connecting Thule License Plate Holder # TH35JV To 4-Way Flat Trailer Connector Wiring
    Yes, you can use the Roadmaster Extension Loop # RM-300150-00 to connect to the Thule License Plate Holder # TH35JV wiring. This will leave you 2 exposed male terminals which will have power and could short out when using the turn signals and brake lights. You can protect this by covering the terminals with some Heat Shrink # DW05450 to seal away the connectors. Or so you do not have so many connections you can cut off the end connectors of the 4-way and 2-wire to connect them with Butt...
    view full answer...
  • Trailer Connector Adapter for Towing a Trailer with a Female 4-Way Trailer Connector
    I am not sure why your kayak trailer came with a female 4-way connector. In the trailer industry, the tow vehicle uses a female style trailer connector and the trailer uses a male style connector. This is the general rule. I have not heard of a vehicle coming with a male style trailer connector of any type. I have attached a photo showing what the vehicle side connector should look like and what the trailer side connector should look like. There are two solutions for this situation. It...
    view full answer...
    Image 1 for
  • 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...
  • Parts Needed to Flat Tow a 2012 Chevy Silverado 1500 Behind a Motor Home
    Given that your 2012 Chevy Silverado 1500 could easily get over the 5,000 pound limit of the base plates you're refering to I recommend going with a different set. The Roadmaster MX base plates, # 3154-3, are generally considered more heavy duty and are recommended for trucks and SUVs. For a compatible tow bar, you will want a Roadmaster model that slides into the hitch on the RV. For a compatible tow bar that will match the capacity of your hitch and cover the vehicle weight, take a look...
    view full answer...
  • Can a 2012 Honda Civic with Automatic Transmission be Flat Towed Behind a Motor Home
    While there are people that flat tow the 2012 Honda Civic automatic, I have found that Honda states that the vehicle should not be flat towed. You will want to consult the owners manual to verify the flat tow-ability of the vehicle. If the owners manual says not to then I do not recommend going against what Honda says. If you find that the vehicle can be flat towed then there are 5 items you will need: base plates, tow bar, safety cables, lighting, and supplemental braking. Blue Ox base...
    view full answer...
  • Parts Needed to Flat Tow a 2009 Pontiac G6 GT Behind a Motor Home
    You can use the Demco base plates # DM9517188 for your 2009 Pontiac G6 GT. But first, you are going to want to consult the vehicle owners manual to determine if the vehicle can be flat towed and if there are any special requirements. From what I found if the vehicle has the 3.9 liter V6 motor it cannot be flat towed. But it is not clear if it can be dolly towed or not. You would need to talk to a GM tech at a dealership to determine if dolly towing is acceptable. If you find that you can...
    view full answer...
  • Estimated Installation Time for Blue Ox Base Plates on a 2013 Ford Edge
    Blue Ox estimates the installation time of base plate kit # BX2628 at 3 hours for an experienced installer. They also add the following comment: The first installation of a particular baseplate, and installation by untrained individuals will likely increase installation time substantially. In addition to the base plates you will also need a compatible tow bar. For the Blue Ox base plates the most popular compatible tow bar is the Avail, # BX7420, which also comes with safety cables. For...
    view full answer...
  • 2004 Hyundai Santa Fe Flat-Towing Parts Recommendations
    To flat-tow your Hyundai Santa Fe you need 5 items. You will need base plates, a tow bar, safety cables, lighting for the towed vehicle, and most states now require supplemental brake systems. For base plates I recommend the Roadmaster XL Base Plate Kit, part # 1619-1. The tow bar I recommend is the Roadmaster Falcon 2 Tow Bar, part # RM-520. For safety cables I recommend part # RM-643. these are 68-inch coiled safety cables. For lighting I recommend the Magnetic LED Tow Lights, part...
    view full answer...
  • Installation Instructions for Trailer Wiring Harness 18252 for a 2008 Smart fortwo
    The trailer wiring harness # 18252 is a universal hardwire type of harness so it does not have vehicle specific instructions because it fits so many vehicles. However, the process for installation is the same for all vehicles. You will use the included circuit tester to test each wire behind the tail lights. The white wire is ground and attaches to a clean bare metal surface. Brown attaches to the running light wire. Yellow is for the left turn signal/left brake light. And green is for...
    view full answer...
  • Roadmaster Extension Loop for Towed Vehicles Wiring Gauge
    The Roadmaster Extension Loop for Towed Vehicles - Dual 4-Way Flat Trailer Ends - 6' Long item # RM-300150-00 uses 18 gauge wires.
    view full answer...
  • 4-Way Flat Vehicle Side Connector that is the Same on Both Ends
    We do have extension loops that are male on both ends. Take a look at # RM-300150-00. It is 6 feet long. This is currently the only option available for a 4-Way flat.
    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 like...
    view full answer...
  • Availability of 8 Foot Long 4-Way Wiring Extension
    We do have 4-Way flat to 4-Way flat extension adapters available, however they do not feature a coiled wire like you mentioned in your question. I recommend taking a look at the Hopkins 4-Pole Flat Wiring Extension # HM48235. This extension measures 120 inches (10 feet) long, which is a bit longer than you need but is the closest option available. We also have a 6 foot extension loop with part # RM-300150-00. I have attached a couple short video demonstrations on these products that...
    view full answer...
  • How to Make 12 inch 4-Way Male to 4-Way Male Adapter
    Since we don't have the exact 4-way adapter you are looking for the best option would be to use two of the # 9653P connectors and cut them both in half and then splice the two male sides together.
    view full answer...
  • Parts Needed to Flat Tow a 2007 Jeep Liberty Behind a Motor Home
    On the base plate kit # BX1122 the tabs are 20 inches apart on center. The only tow bars that can be used are the Avail, # BX7420, Aventa, # BX7445, Alpha, # BX7380, and Allure, # BX7460P. The most popular of these is the Avail. It also comes with safety cables so you would not have to add any. You will also need a lighting solution to flat tow the vehicle. I recommend the bulb and socket kit # RM-155. It will bypass the vehicle wiring so you will not have to splice into it. Most states...
    view full answer...
  • Parts Needed to Flat Tow a 1993 Jeep Wrangler Behind a 2007 Chevy Suburban
    For the 1993 Jeep Wrangler, we only have base plate options (that connect to the tow bar) if the Jeep has a U-channel bumper. You can use base plates # 1409-3. These base plates are compatible with your Roadmaster Falcon 2 tow bar, # RM-525. In addition to the base plates and tow bar, you will also need safety cables like # RM-643, a lighting solution, and a supplemental braking system. For lighting there are several options. If you will not be towing often then I recommend a magnetic...
    view full answer...
  • Parts Needed to Flat Tow a 2009 Ford Escape Behind a Motor Home
    Base plates are sold separately from the other components you will need to flat tow your 2009 Ford Escape. The first thing you will want to do is consult the vehicle owners manual to determine if the vehicle can be flat towed and if there are any special requirements or procedures to follow if it can be flat towed. The base plate kit # DM9518219 includes everything needed to install the base plates to the vehicle. The safety cables are not included, however they are included with the...
    view full answer...
  • Flat Towing Base Plates and Tow Bar Set-Ups for 2016 Buick Enclave
    Flat towing a vehicle behind an RV requires 5 basic components: 1) tow bar, 2) safety cables, 3) wiring kit and 4) base plates and 5) a braking system for the towed vehicle. The linked articles will give you good general background on each of these. I checked with my technical contact at Roadmaster and they do offer base plate kit # 523149-1 which fits Buick Enclave models (without brushguards) up through the 2016 model year. I suggest their Falcon 2 Tow Bar, part # RM-520, since it will...
    view full answer...
  • Can the Wiring on Magnetic Mount Stop, Turn and Tail Towing Light Kit Be Extended
    You can add additional wire if you need to on light kit # TL21RK. You can cut and splice in the appropriate length of bonded 4-wire, # 16-4B-1. It is sold in 1 foot increments so if you needed 10 feet you would enter 10 in the quantity box. And you can use butt connectors, # 05731-5, to make the splices. I do recommend wrapping the connections in electrical tape to further protect them. Another option that will not require cutting and splicing is to use extension loop # RM-300150-00. It...
    view full answer...


< Previous
12



Do you have a question about this Flat Tow Wiring Harnes?


Info for this part was:

Employee Frances L
Edited by:
Frances L
Employee Jameson C
Expert Research:
Jameson C
Employee Adam R
Expert Research:
Adam R
Employee Jeffrey L
Expert Research:
Jeffrey L
Employee David L
Written by:
David L
Employee Laura H
Updated by:
Laura H
Employee Wilson B
Updated by:
Wilson B
Employee Cole B
Installed by:
Cole B

At etrailer 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.