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Hopkins 4-Way Flat Trailer Connector w/ 48" Harness

Hopkins 4-Way Flat Trailer Connector w/ 48" Harness

Item # HM48035
Our Price: $4.76
Trailer Wiring
Shipping Weight: 0.23 lbs
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If you already have the tools and hardware needed for installation, this no-frills, universal, splice-in, 4-way flat connector will get you towing in no time. Color-coded bonded wires have functions printed on them to make installation easier. Great Prices for the best trailer wiring from Hopkins. Hopkins 4-Way Flat Trailer Connector w/ 48" Harness part number HM48035 can be ordered online at or call 1-800-940-8924 for expert service.
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Hopkins Trailer Wiring - HM48035

  • Trailer Connectors
  • Vehicle End Connector
  • 4 Flat
  • Plug and Lead
  • 0 - 5 Feet Long
  • Hopkins

If you already have the tools and hardware needed for installation, this no-frills, universal, splice-in, 4-way flat connector will get you towing in no time. Color-coded bonded wires have functions printed on them to make installation easier.


  • Provides a 4-way flat trailer connector at the back of your vehicle to power your trailer's signal lights
    • Compatible with 5-pole, 6-pole, and 7-pole adapters (sold separately)
  • Works with 2-wire electrical systems
  • Splices into your vehicle's wiring
    • Bonded wires are color coded (see wiring configuration below) and labeled
    • Wire connectors sold separately
  • Includes durable, molded-rubber, standard female output socket


  • Harness length: 48"
  • Max amperage: 2.5 amps per circuit
  • Wire gauge: 14
  • 90-Day Warranty

4-Way Trailer Connector Installation

Because the color/function of the wires on this connector may not match the color/function of those on your vehicle, be sure to use a tester (sold separately) to double check the function of each wire on your vehicle's tail light wiring harness before installing this connector. Once you've figured out the functions of your vehicle's wiring, use quick-splice or butt connectors (sold separately) to connect the corresponding wires on the trailer connector.

The number 1 reason trailer wiring comes up faulty is a bad ground, so make sure your ground wire has a solid and clean connection to metal. To make this connection, you'll need a ring terminal and a self-tapping screw (sold separately).

Wiring Configuration

Wire Color Wire Function
Green Right turn and brake light
Brown Tail lights and running lights
White Ground
Yellow Left turn and brake light

Quick Tips:

We install a lot of wiring harness around here, so we thought we'd share a few tips we've picked up over the years:

  • Butt connectors - especially heat-shrink ones - provide the most secure, longest-lasting connection, so we'd recommend you grab a few and swap them out for the quick-splices in this kit.
  • Use a circuit tester on the plug terminals once the harness is installed to make sure everything's working. There's nothing worse than figuring out that you have a bad ground or a faulty connection right before you're about to hit the road.
  • Be sure to put a little bit of dielectric grease on the 4-way plug to protect the terminals from dirt, grime, and corrosion.

48035 Hopkins Vehicle Wiring Harness with Vehicle End 4-Pole Connector - 4' Long

Installation Details HM48035 Installation instructions

California residents: click here

Customer Satisfaction Score:

Customer Reviews

Hopkins 4-Way Flat Trailer Connector w/ 48" Harness - HM48035

Average Customer Rating:  4.9 out of 5 stars   (50 Customer Reviews)

If you already have the tools and hardware needed for installation, this no-frills, universal, splice-in, 4-way flat connector will get you towing in no time. Color-coded bonded wires have functions printed on them to make installation easier.


SMI Stay in Play Duo installation in 2015 Jeep Wrangler Unlimited –
Packaging was great with everything needed included plus extra items for various installation methods of you’re choosing. Upon initial investigation and survey, everything except the CD Information pack was accounted for.
No big deal, as I had previously watched 2 different Youtube installations found on the internet. In fact, the internet videos were what I used as my step by step installation process, and the written instructions were only used for concerns where the video may not have been as clear as I had hoped for.
Understanding that everyone has their own style and methods for doing this project, I purposely was not in a hurry to rush through it. All in all, I took @ 8 hours to install the Adapter 4 to 6 pole #30637, the EZMount Tow lights Kit, and the Stay in Play Duo Braking System.
I choose the EZMount because I didn’t want to mess around with the OEM taillights and wiring. Magnetic lights don’t work so well on composite tops and I didn’t want to stick them to the sides of te Jeep, so I modified the EZ mount to wrap around the thickness of the rear glass hatch on both sides. I added a 2”x 4” pc of Velcro on the inside of the glass hatch and the mating surface of the plastic light housing - to hold the lamps in place until the rear gate was closed.
I ran the wire harness on the inside under the trim all the way up to the front and through the grommet in the firewall. The flat 4 wire was routed and secured up to the Adapter 4 pole to 6 pole that I had fastened to the Blue Ox base plate.
The actual installation of the SMI unit and assorted parts went rather smoothly. Most difficult issue was the lack of working space in front of the driver’s seat area. Installing the screw that holds the G force controller on the front (the side towards the front of the car) was difficult as it was almost a blind installation due to lack of room. The nut and fender washer used through the fire wall for attaching the air cylinder cable bracket was a challenge to reach - tight fit with not much room for one's hand and arm.
Other than that, no big surprises – just a lot of tedious steps to do when you want to be sure that it is being installed properly – take your time and don’t be in a hurry.
Once everything was installed – it all worked when I checked the system out. The only thing that may seem a bit odd is that when setting the G force initially, the compressor will shut off while adjusting per instructions. To do this initial adjustment, the wife stepped on the brake in the Motorhome, with the switch “On”. The compressor starts, and the brake is pushed down by the Air Cylinder, at which time I slowly adjusted the G force until the compressor shuts off. I secured the adjusting bolt and I told the wife to take her foot off the brake and then re-apply them. The compressor did not start again and the air cylinder did not apply the brakes in the Jeep. After setting the G force per instructions, the unit didn't turn on when the brakes in the Motorhome were applied - but since we were not moving - all I can assume is that the brake system will function while slowing down once the accelerometer setting (the sensitivity setting on the G force box) has been met. I assume that the sensitivity setting method includes a way to ensure the Jeep brakes are not engaged too frequently and only until needed.
This is the only step that is a tad bit confusing without an explanation as to what to expect once the G force sensitivity is set.
Lastly, I checked the brake away switch and it turned the compressor on and applied the brakes as expected.
Overall - the installation went rather smoothly. Can't wait to see how the product works once we hit the road. I'll check back and provide an update later.


looks okay.


Ordered this Hitch for a 1998 Ford F-150. It was ordered late Thursday night, and was setting on my front porch Monday morning. This is some of the fastest service I have experienced for a large item. My compliments to your shipping department.
The F-150 has a 17 inch spare so no need to drop it. the hitch went right up. Two men lying under the truck had it mounted, and torqued down in less than 30 minutes. Beautiful hitch, and really well made, and since I have built several Class IV hitches from scratch I know what I'm talking about.


I bought wiring and connectors to rewire a 30+ year old utility trailer. All items purchased were of excellent quality and the trailer lights work well. I was especially pleased with the jacketed 4 conductor wiring.


The customer service at etrailer is, as always, excellent. My product shipped quickly and arrived soon after I ordered. The videos and instructional material were very helpful in ensuring I was purchasing the correct product. For trailer or trailer related products I will not shop anywhere else. I needed this because my old harness had corroded terminals. This will be simple to replace.


I am very happy with Rebecca's help over the phone and assisting me with ordering my wiring harness with bracket on my 2015 Chevrolet Colorado. I received exactly what I need. Would recommend Etrailer to anyone. Thanks Rebecca and Etrailer


Wire harness seems to be well made. Fits my trailer plug perfectly. Great price from etrailer, and pretty quick shipping as well. This is my second purchase from etrailer and I couldn't be more pleased with both transactions.


The product will be replacing an existing pigtail that is showing signs of corrosion on the terminal ends and sometimes need a light wire brushing to make electrical contact. The terminals on this piece appear to be a better metal and time will tell if they resist the corrosion any better.


I haven’t installed the wiring yet, but if I have a problem it won’t be because of etrailer since they didn’t make the wiring harness. Will do this tomorrow.


Awesome product


Glad they carry Hopkins products. I prefer Hopkins over others because the wiring plastic insulation is heavier. Excellent quality product.


An amazing wealth of products.
And an
even greater knowledge base to draw on for info and direction. is my favorite "bookmark"


Great, well-made product at an outstanding price!


Super simple to install and it followed the installation video exactly.


Product was received promptly and worked great on an older Jayco popup camper. I would use etrailer on future purchases for any of my trailer needs!


Great stuff to work with. Pallet racks and etrailer parts


wiring harness of good quality, just as shown, thanks


Quick and easy to connect


Works fine

Bob D.


works just right


I've always gotten good quality products and if there was a Problem Prompt an Courteous Responses,,Thx for always being Professional,,,


Not much to say but it works




Works great so far.


great prices and prompt shipping

Show More Reviews

See what our Experts say about this Hopkins Trailer Wiring

  • Installing 4-Way Trailer Connector on 2000 Dodge Grand Caravan
    Your 2000 Dodge Grand Caravan uses a separate wiring system, meaning that the brake and turn signals are sent along separate wires. Because of this, a converter is required and you will not be able to use the Hopkins Wiring Harness with 4-Pole Flat Trailer Connector # HM48035 referenced in your question. To install a 4-way connector on your Grand Caravan, I recommend using the Tekonsha T-One Vehicle Wiring Harness # 118334. This includes the needed converter and the T-One connector will...
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  • Towing Trailers with 4-Way Connectors Using a Vehicle With a 5-Way Connector
    Actually, you don't have to change anything. The 4-way connectors on your trailers fits into the 5-way on the vehicle except you'll have an extra pin not being used. Since it's the trailers that are missing a pin that means you don't need that function, which is likely a reverse light circuit. If you want you can replace the connectors on both trailers with a 5-way like part # HM47910 but you still won't use the function of the fifth pin. The other option is to replace the 5-way on...
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  • Adapter Harness to Convert Tekonsha/Hopkins Male Plug to Female Plug
    It sounds like you're trying to convert one of the male ends to female. If that is correct you need an adapter with female on both ends so you can use the the # HM48035 and add the # HM48190 to the other end. There are no premade adapters so this is the simplest solution. You could also cut off one of the male ends you and add the # HM48190 so you have less parts to purchase.
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  • 5-Way Flat to 4-Way Flat Adapter To Connect To Trailer and Dexter Surge Brake On EZ Loader Trailer
    It sounds like you are needing the opposite of the Tow Ready 4 Pole to 5 Pole Trailer Wiring Adapter # 20036. As we do not have the same type of adapter with the opposite male and female ends you could build one using the 5-Flat # HM47910 and 4-Flat # HM48035 ends. Then you will be able to run the additional wire to the Dexter surge brake for your reverse lockout. I hope this helps you Jim, since we do not carry the EZ loader specific adapter.
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  • Recommendation For A Wiring Harness That Is 60 Inches Long
    Yes, I have what you are looking for! The Curt Vehicle Wiring Harness with 4-Pole Flat Connector, Item # C58044, is very similar to the Hopkins Wiring Harness, Item # HM48035, that you referenced. It is a universal wiring harness kit with all the necessary hardware needed for installation that is 60 inches long. I have attached a video for you to check out.
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  • Adding A 4-Pole And 7-Pole Connector To A 2005 Chevy Silverado
    If you don't have a factory connector like the one pictured below then you'll have to do a bit of splicing in wire and unfortunately won't have an easy plug-in installation. You'll want to pick up a 4-pole wire harness # HM48035, some extra 14 gauge wire, heat shrink butt connectors, self-tapping screws, and a spade terminal. The white wire will run to your frame and can be secured with a ring terminal and self-tapping screw. The rest of the wires will need to splice into their respective...
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  • How To Install A Wiring Harness For Towing On A 1972 Volkswagen Bus Campmobile
    I do have a trailer wiring harness option for you to consider however, there are no t-connector wiring harnesses for your 1972 Volkswagen Bus Campmobile. In order to install a wiring harness on your vehicle for towing, you will need to hardwire in a harness such as the Hopkins Wiring Harness with 4-Pole Flat Trailer Connector part # HM48035. The white wire will need to be grounded to the chassis, the brown wire will be spliced into the vehicle's tail lights, the yellow wire will need...
    view full answer...
  • Replacing 4-Way Flat Connector With No White Ground Wire Causing Lights To Turn Off
    You are correct that you need a ground wire for your 4-way flat connector. When you are hitting bumps the coupler for the ball has a small amount of play inside which is causing your lights to turn off and on. The Hopkins Wiring Harness # HM38138 will give you a short 4' lead which you can splice into your trailer wiring and run the white wire to a good ground location on the trailer. This will ensure a good solid ground connection for the wiring on the trailer. The Heat Shrink Butt Connectors...
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  • Trailer Wiring Harness for a 2005 Ford Escape
    Your 2005 Ford Escape has what is called a separate or 3-wire system. This means that it has turn signals and brake lights that are on different circuits. Trailers have what is called a combined or 2-wire system which means the brake lights and turn signals are on the same circuit. In order to have the proper functions from a vehicle side 4-Way you will need a wiring harness that has a converter. The converter takes the separate signals from the vehicle and combines them so that the 4-Way...
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  • 4-Way Flat Wiring Connector For Hopkins Knockout Adapter On Dump Trailer
    You can use the Hopkins Wiring Harness # HM48035 to connect to the Hopkins Knockout Adapter # HM47605. This has 4 wires 48" long that you will be able to wire in using the Heat Shrink Connectors # DW05744-5. Since your original only has 3 wires you will need to connect the white wire to a good ground connection since the previous must have broke off.
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  • Will the 7-Way Round Pin to 4-Flat Adapter Work On a Semi
    I do have an option for you but the 7-Way Round Pin to 4-Flat Adapter part # 47405 won't work on semi's as there is no converter integrated into the adapter. The lights on a semi are separate and the lights on a trailer are combined so a converter is required. Therefore, you will have to make your own adapter using the Hopkins Tail Light Converter part # HM48847, 7-Round Connector part # PK11700, and Hopkins Wiring Harness with 4-Pole Flat Trailer Connector part # HM48035.
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  • Availability of a Replacement 4-Way Vehicle Side Plug End
    I have a solution for you. The Hopkins Wiring Harness, # HM48035, will replace the malfunctioning 4-flat plug on your vehicle. You will just need to cut off the current plug and using Deka Heat Shrink Butt Connectors, # DW05744-5, connect the new plug to your wiring harness.
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  • Connecting Motorcycle with 6-Way Flat to Trailer with 4-Way Connector
    Motorcycle trailer wiring typically has separate circuits for the stop lights and turn signals while trailer wiring will have these circuits combined. You can verify this by testing the pins on the 6-Way with a circuit tester like # PTW2993 while somebody runs through the lighting functions. If this is the case, then you will need to use a converter # RM-732 on the motorcycle wiring to convert the lighting functions before the connector. A 6-Way flat is not a standard connector and there...
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  • Converting Wiring On 1998 Ford Ranger From 4-way To 7-Way For Trailer
    We have what you need to convert your wiring from 4-way to 7-way to match your trailer. You can cut the round connector off on the vehicle side and replace it with part # HM48035. Then you need to use part # ETBC7. Your 4-way flat will plug into the # ETBC7 and you will need to run the additional wires. You will need to attach the white wire from the # ETBC7 to a clean bare metal surface for a ground. The blue wire will go to your brake controller. The purple wire is used for reverse...
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    Image 1 for
  • Are Hopkins 4-Pole Flat Connector Pigtails And Their Mounting Accessories Available
    For the Hopkins 48015 you can use the Hopkins 4-Way Flat Trailer Connector w/ 48" Harness # HM48035. For the 48735 you can use the Curt 4-Way Flat Wiring Connector Cover # C58200. We do currently offer the 48595 with part # HM48595. For the 48015 and 48735 you could also use the Hopkins Endurance Easy-Pull 4-Way Flat Trailer Connector w/ 48" Harness # HM48044 as well.
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  • How to Install Wiring Harness 118496 in 1995 Toyota T100
    The installation of a 4-flat connector such as the T-One Vehicle Wiring Harness # 118496 in your 1995 Toyota T100 is a very simple and straightforward process; it only requires plugging in the T-connectors at the taillight wiring harness. I was unable to locate what harness you ordered from us so I'm not certain what exact harness you used but the process should not be any different (see linked installation video which shows how this harness installs). If you only cut off the connector...
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  • Can 2019 Jeep Wrangler Use Hardwired 4-Flat Wiring Harness
    Yes, you can use the Hopkins Wiring Harness with 4-Pole Flat Trailer Connector # HM48035 on your 2019 Jeep Wrangler if you want to hardwire a 4-flat, though I do recommend the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118786 which fits your '19 Jeep and includes a power module connected to your battery. This is important because you won't overload your electrical system with this harness, something that will protect your Jeep in a way the Hopkins harness cannot....
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  • Adapter Needed for External Battery to Trailer Side 4-Way
    We do not have a direct adapter, but you could very make your own. Using alligator clips and the Hopkins Wiring Harness # HM48035 would allow you to do this. I do recommend installing at least a 15 amp fuse # C58450-1 and Fuse Holder # SWC9538 between the 4-Way and the battery to keep your setup safe in case of a short.
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  • Parts Needed To Install a 7-Way On a 2004 Chevrolet Silverado
    I'm not sure what the square plug you have goes to but on a 2004 Chevrolet Silverado tow wiring it would have round connector like you see on the Replacement Connector # 30955. If you do not have this we do have the 7-Way Upgrade # ETBC7 which will allow you to connect to the 4-Way # HM48035 which was already installed. It includes wiring for a charge line which will also allow you to use the Curt Echo # C51180.
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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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  • Replacement 4 Flat Connector for a 2013 Ford Explorer
    We definitely have replacement options for a 4 Flat on your 2013 Ford Explorer. I am including a full replacement for your T harness, as this is what I suggest doing, but also an option to cut off the end of your 4 Flat and splice on a new end. The Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat # 118540 will be a full replacement for your damaged harness. This is a plug and play harness that will take at most 10 minutes to get installed. Due to all this, I recommend going this...
    view full answer...
  • Trailer Wiring Adapters Available for 7-Pin Flat to 4-Pin Round Connectors
    I have some wiring adapter options for you, but if your vehicle has a 4-Pin round connector, like # PK11404, we only offer adapters to connect to 4-Way flat trailer connectors and tow bar wiring extensions like # HM47043 that you referenced. If you're looking for a wiring adapter to allow you to connect a trailer with a 4-Way flat connector, like # 18004, to your vehicle's end 7-Way blade-style socket, like # PK11893 we have an adapter that will work great. For this set-up, you can use...
    view full answer...
  • 4-way Round Trailer Connector to 4-way Flat Connector
    I have a solution for you. However, we do not have an adapter to fit your 4-pin round connector on your trailer. Because of the rarity a 4-way round connector, I recommend either cutting off the 4-way round and attaching a 4-way flat, or splicing a 4-way flat into your wiring in addition to the 4-way round. To attach a 4-way flat, you can use part # HM48035. If you remove your 4-way Round connector, you will want to use butt connectors # DW05744-5. If you want to add the 4-way Flat...
    view full answer...
    Image 1 for
  • Installing Additional Brake Light to Mount on Kayak that Overhangs Trailer
    First, to replace the 4-way connection on your trailer with a 7-way, you can use the Pollak Black 7-Pole, RV-Style Trailer Connector - Trailer End # PK12706. You will just cut the wires on the existing 4-way and splice them into this connector. Then to add the connections needed on your trailer to use the Optronics Thinline LED Trailer Tail Light # STL59RB as a portable option for use at night, you can use a vehicle end 4-Pole Flat connector like the Hopkins # HM48035 that will come off...
    view full answer...

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