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

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

Part Number: RM-300150-00
In Stock
$35.66
Flat Tow Wiring Harness
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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.
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  • Reviews (35)
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  • Videos (1)
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Roadmaster Flat Tow Wiring Harness - RM-300150-00

  • Adapters
  • Extension Cord
  • Plugs into Vehicle Wiring
  • Universal
  • Roadmaster

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




California residents: click here


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

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

35 reviews
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.

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:

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:

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:

Easy to install and needed for extending the wiring for the tow hitch.



by:

First time buying a tow bar. Great experience with Jesse at errailer. etrailer videos are excellent.



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:

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:

Exactly what I needed for towing my Jeep. Arrived quickly. The pigtail currently on there was too short.



by:

Perfect! Hard to find this cable in local stores and etrailer not only had it, but at a great price.



by:

Chelsea was an amazing product specialist! Knowledgeable and professional.



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:

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 delive ry.



by:

This is what I needed



by:

Fast Shipping. Product as described.



by:

Product was delivered as the picture lo oks



by:

Great service and availability, as alwa ys!



by:


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Show More Reviews

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

  • 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...
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  • 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...
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  • 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...
  • 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...
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  • How To Make a Trailer Wiring Harness Adapter with Two Vehicle Side Trailer Connectors
    In order to obtain a trailer wiring harness with two vehicle side trailer connectors you will need to either splice two of the Hopkins Wiring Harness with 4-Pole Flat Trailer Connector part # HM48035 into one another with the Deka Heat Shrink Butt Connector part # DW05744-5 or you could just install the Hopkins Endurance Quick-Fix Replacement 4-Way Flat Trailer Connector part # HM48190 onto the opposite end. Unfortunately, we do not have a complete trailer wiring harness like the Roadmaster...
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  • Will Roadmaster Blackhawk 2 Tow Bar Work with Roadmaster Base Plates for a 2010 Honda CR-V
    Yes, the Blackhawk 2 All Terrain tow bar will fit the XL base plates # RM-521559-4 for the 2010 Honda CR-V. Since you have already been flat towing, you probably already have safety cables but in case you do need cables use # RM-645. These are straight cables that you can use in the cable guides on the Blackhawk tow bar. You will also need lighting for the CR-V. If you are using a magnetic kit like # RM-2120 or something similar then you can continue to use that with the CR-V. If you want...
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  • 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. You...
    view full answer...
  • Availability of 4-Pole to 4-Pole Trailer Wiring Extension
    We do offer both 4-foot and 6-foot 4-pole trailer wiring extensions that you can use to extend your trailer connector. For a 4-foot extension use part # HM47115; for a 6-foot extension use part # RM-300150-00.
    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...
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  • 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...
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  • 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.
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  • 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.
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  • Parts Needed to Flat Tow a 2012 Jeep Wrangler Sport Behind Winnebago 35U Gas Coach
    Flat towing requires 5 basic components: tow bar, safety cables, a wiring/lighting kit and base plates and a supplementary braking system for the towed vehicle. Since you have a Roadmaster tow bar I suggest staying with their base plates since this will avoid the hassle and expense of adapters which can be required to mate different brands' parts. You can use the link provided to see all Roadmaster base plates and the Select Vehicle Style drop-down menu at the top of the page will allow...
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  • 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...
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  • Recommended Tow Bar and Base Plates for Flat-Towing 1952 Dodge Panel Truck
    We do not offer any custom-fit base plates for your 1952 Dodge panel truck but Blue Ox makes a set of heavy-duty bolt on base plates designed to mount to a flat section of bumper, part # BX88230. Since this will be a custom installation you will need to make sure the bumper has the necessary weight capacity for towing the truck. Most bumpers will require reinforcement. With these installed you can use any Blue OX tow bar, such as their car-mount Acclaim # BX4330 that you referenced. This...
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  • 4-Way Prong Wiring Needed That is 8' Long
    If you are looking for just an extension then the Hopkins 4-Pole Flat Wiring Extension # HM48235 that you referenced is 10' long and will be exactly what you are needing. For a flat towing application we have the common 4-Way round connectors like part # HM47046 which is 8' long or for a 4-Way flat connector you would need both the part # RM-300150-00 (6') and the part # HM47004 (2'). Let me know if you are looking for something different and I can make a recommendation for you.
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  • Parts Needed to Flat Tow a 1995 Jeep Wrangler with a Falcon 5250 Tow Bar
    Tow bars are not vehicle specific but the base plates are. You can use the Falcon 5250 tow bar with your 1995 Jeep Wrangler as long as you first install the correct base plates, see link. Either set will be compatible with the 5250 tow bar. You will also need safety cables like # RM-643, a lighting solution, and supplemental braking. Also check the vehicle owners manual for more information on recreational towing of the Wrangler. For lighting there are several possible options. If you...
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  • 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.
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  • Parts Needed to Flat Tow a 2004 Jeep Grand Cherokee Behind a 2007 GMC Sierra 2500
    In order to flat tow a vehicle, the very first thing you are going to want to do is consult the owners manual in the recreational towing section to determine the correct towing procedure. If you find that the vehicle can be flat towed then you will need 5 items. First you will need base plates on the vehicle being towed or the Toad. The base plates provide the proper safe and secure attachment point for the tow bar. You can use base plates # 1425-1. I have included a link to a video showing...
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  • 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...
  • Recommended 4-way Connector Needed for Tow Daddy Wiring Harness for Dinghy Towing
    Sounds like you are looking for the just the Vehicle End 4-way flat trailer connector like the Hopkins # HM48190. This will mate with the wiring kit you have and connect to your male end 4-way plug # RM-300150-00 that you also purchased. I have linked all the above mentioned products to this page for your convenience.
    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
  • Trailer Wiring Extension to Go From Motor Home to Flat Towed 2008 Mazda MX-5 Miata
    What you need is the Roadmaster extension loop, # RM-300150-00. This is a 6 foot long cable with 4-Way ends. Both are male ends which is what you should need (the motor home and front of vehicle should have the same female connector). I have included a couple of helpful links to our FAQ articles on flat towing for you as well.
    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...


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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

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