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Hopkins Wiring Harness with 5-Pole Flat Trailer Connector - Vehicle End - 5' Long
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Hopkins

Hopkins Wiring Harness with 5-Pole Flat Trailer Connector - Vehicle End - 5' Long

$11.72
Custom Fit Vehicle Wiring
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Wire your vehicle to tow a trailer with this universal, splice-in wiring harness. Provides reverse function to release surge brakes. Corrosion-resistant terminals are long-lasting. 1-800-940-8924 to order Hopkins custom fit vehicle wiring part number HM37908 or order online at etrailer.com. Free expert support on all Hopkins products. Great prices and Fastest Shipping for Hopkins Wiring Harness with 5-Pole Flat Trailer Connector - Vehicle End - 5' Long. Custom Fit Vehicle Wiring reviews from real customers.
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  • Reviews (17)
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  • Videos (2)
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Hopkins Custom Fit Vehicle Wiring

Highlights

  • Ready for 5-Wire Trailers: 5-pole flat connector adds reverse or brake-lockout function.
  • Simple Splice-In Fit: Color-coded wires match standard trailer wiring for easy hookup.
  • Reliable Grounding: White ground wire ensures stable power for trailer lights.
  • Flexible Length: 5-ft lead gives enough reach for routing from tail light area.
  • Durable Build: 16-gauge wire delivers long-lasting, consistent signal power.

Features to know about

Simple Upgrade for Trailer Lighting: 5-Pole Flat Connector with 5' Lead

If you’re adding reverse lights or a brake lockout to your trailer setup, this harness makes it easy. The Hopkins 5-Pole Flat Vehicle-End Connector gives you the standard lighting functions—running lights, left and right turn signals, and brake lights—plus a dedicated blue wire for reverse lights or electric lockout solenoids. The 5-foot long lead gives you enough wire to reach a clean connection point without stretching or adding extensions.

Straightforward Wiring for Dependable Results: Splice-In Design

This splice-in plug-and-lead harness keeps wiring simple and direct. Each wire is color-coded for function: white for ground, brown for running lights, yellow for left turn/brake, green for right turn/brake, and blue for reverse. Just match color to color, connect the blue lead to your reverse circuit, and you’re ready to go. No extra adapters needed when you want that fifth function working properly.

Versatile Fit for Different Trailer Types: Universal 5-Flat Connection

The universal 5-flat design connects cleanly with standard trailer wiring setups. It fits easily into existing installs or when upgrading a 4-way to include reverse power. If your trailer doesn’t use the fifth pin, it simply remains unused without affecting the rest of your lighting functions.

Reliable Trailer Operation Every Time You Tow: No Converter Needed

Built without a converter, this harness delivers direct signal flow from your vehicle circuits for consistent lighting response. The sealed flat plug design ensures solid electrical contact and dependable performance whether you’re towing a utility trailer, boat trailer, or small camper.

Specs

Wiring and Electrical Specifications

  • Wire gauge: 16 gauge

37908 Hopkins 5-Way Flat Connector - Vehicle End - 60"

Item # HM37908





Video of Hopkins Wiring Harness with 5-Pole Flat Trailer Connector - Vehicle End - 5' Long
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Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for In-Depth Review of the Hopkins Wiring Harness with 5-Pole Flat Trailer Connector

Hey, everybody. Ryan here at etrailer. Today, we're gonna be checking out the Hopkins 5-way flat trailer connector for your vehicle side. For those of you that are unfamiliar with a five-way flat, this is essentially identical to kind of your classic four-way flat type connector. I'm sure a lot of people have seen them. They're just on about a ton of different medium size, smaller size trailers.

But this being the five-way though, you get one extra signal and that will be your reverse light signal. So, we have our ground wire, our taillight signal, our left turn as well as stop, right turn and stop, and this blue one is our reverse light. Now, there's a couple of different reasons you would wanna use this. I'd say probably the most common is for when you're towing a boat that has surge brakes on it. That way, when you're going to launch the boat or just even back it up into the garage or whatever, it'll have this reverse light signal and it won't lock the brakes up.

That way, you can actually back it up and not, you know, drag it across the ground. But you can kind of get creative too. I know there's some people that use this signal. They might have some small LED lights like as back up lights on their utility trailer and you can get a signal from this. That way, when you put it in reverse, it sends power out to whatever you have it wired up to.

So, you can kind of get creative on what you can do with this. Now, keep in mind this isn't gonna have a ton of amperage. So, you can't run a hundred lights off of it. But you got one or two lights on it, especially if they're LEDs, chances are good it's gonna power them right up and everything else. So, you know it's one of those deals that, in a sense, it's almost an upgrade over kind of your factory four-way or your regular four-way type connector.

And that kind of brings me to my next point. You are still able to use a four-way connector with this. So, let's say, if you have a boat trailer with the five-way and you also have the utility trailer with the standard four-way, you're still gonna be able to use the same connector. You won't need an adapter or anything. So, just for example, this is a trailer side, kind of your standard four-way and it'll still plug in. It'll still get its regular signals and everything else. So, like I said, you're not gonna need an adapter or anything like that. But I do want to mention, for this to work, you are going to need existing four-way wiring because this is essentially just a pigtail, right So, it's the connector and those five wires that come off of it. So, you are gonna have to kind of splice this into your existing wiring. And then, of course, you're gonna need to be able to find a way to pick up your reverse light circuit too. Whether it be your reverse light bulb, maybe your reverse light fuse in the dash or whatever, you're gonna need that power source, right So, that's just something to keep in mind whenever you're thinking about hooking this up to your vehicle. This particular harness is going to be five foot in length. So, changes are pretty good you're not gonna need all that wiring but it is good to have, right That way, if you do have to stretch it a little bit further, you got it, which kind of brings me to my next point. When installing this, it's probably a good idea, I would suggest picking up five heat shrink-type butt connectors, especially if you're gonna be keeping this outside since you have to splice in your existing four-way wiring. And it's gonna be pretty much the same for all vehicles. You splice in that four-way and then obviously, pick up your reverse light circuit, which like I mentioned earlier, you usually get it from your reverse lights, or one of your fuses, things like that. So, every vehicle is gonna be a little bit different but the idea is the same. I do wanna mention too, this isn't gonna come with a dust cover. You know how sometimes there's a little cap that'll plug over this So, that is something that you can grab separate and excuse me, you can also get, there's all different types of brackets and things of that nature where you can mount this up on your hitch. And this is even a good example. So today, I just put some of this black wire loom over our wires just to help kind of, kind of help it blend in a little bit better. So, you can use something like this as well if that's the style you're going for or the look you're going for. But other than that, at the end of the day, it's gonna be a good way to be able to use different types of accessories or pull those different types of trailers around that you otherwise wouldn't be able to. So hopefully, this kind of cleared up a few things and answered some of your questions on what this is, and what it actually does, and gets you going in the right direction. And that'll finish up our look at of the Hopkins five-way flat trailer connector for the vehicle side..

Customer Satisfaction Score:

Ratings & Reviews

4.9

17 reviews
Review sort icon
Wire your vehicle to tow a trailer with this universal, splice-in wiring harness. Provides reverse function to release surge brakes. Corrosion-resistant terminals are long-lasting.

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Haven't used it yet but pretty straight forward.



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Just what I wanted. No frills straightforward ready to install. Good value and quality.



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Great product. Just what I needed.



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The product was good, but it took 45 days to get it.



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Good product. Would be even better if wire was tinned copper



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The Glolight LED trailer set is the perfect replacement for my tow dolly. It is light weight and much more visible than the standard bulb lamp set the trailer was equipped with. Installation was quick and very easy, I will recommend this to all needing to change theirs out...



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Great Prices and Fast Shipping



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Thank you for shipping it out fast. Plan to use it for my motorcycle.


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See what our Experts say about this Hopkins Custom Fit Vehicle Wiring

  • What are the Functions of Trailer Light Green, Yellow, and Brown Wires
    Normally, the green wire on the right side carries right turn signal and brake light functions and the brown wire carries running light functions. On the left side, the yellow wire carries left turn and brake lights and the brown wire again carries the running lights. With only 2 wires, these lights must ground through the mounting studs. Make sure to wire in the new lights by function to the existing trailer wiring and not by color.
    view full answer...
  • Wire Gauge of 5-Pole Flat Vehicle Wiring Harness and Recommended 5-Flat Trailer Side Harness
    The 5-Pole Flat Vehicle Wiring Harness # HM37908 uses 16 gauge wire.
    view full answer...
  • Trailer Connector for Towing Surge Coupler Equipped Trailer With 2013 Toyota Tundra
    I'll begin with the assumption that your new pontoon trailer has hydraulic surge brakes. This type of braking system uses a hydraulic coupler that compresses when the tow vehicle brakes, and the compression is what causes the brakes to actuate. A trailer like this usually uses a 5 pole flat trailer connector, with the extra circuit being the reverse lock out. The reverse lock utilizes a solenoid that prevents the brakes from applying with you attempt to back the trailer. Otherwise, especially...
    view full answer...
  • 7-Way to 6-Pole Trailer Connector Adapter for Horse Trailers
    Most horse trailers have a 6-pole trailer connector. In order to attach the 6-pole trailer connector to your vehicle then you will want to use the Hopkins Heavy-Duty, Coiled Trailer Connector Adapter part # HM47083 if the center pin on your vehicle connector is for 12v power or part # HM47085 if the center pin on your vehicle connector is for the brake circuit. You will need a 7-way connector on your vehicle in order to activate the trailer brakes on your horse trailer. If you do not...
    view full answer...
  • Connecting a 5-Pin Trailer Wiring Harness for Motorcycle to a Trailer with 4-Way Flat Plug
    The Hopkins Taillight Converter Kit with 4-Way Flat Connector # HM48895 will work as long as you do not mind having a 4-way connection on your motorcycle. You will have to remove the 5-pin connector and wire the converter on the motorcycle to reduce its 5-wire system to a 4-wire system. Your trailer should be wired as follows: White wire = ground brown = taillight yellow = left turn and brake green = right turn and brake Attach the white ground wire to a suitable ground on the motorcycle...
    view full answer...
  • Wiring a U.S.A. Boat Trailer to a 9 Wire European Trailer Plug
    The 5-Way connector on your boat will be wired as follows. Green is right turn/brake, yellow is left turn/brake, brown is running lights (both sides), white is the ground or earth connection, and the blue wire is the reverse lockout or reverse lights. I searched for a connector on the internet that matches your 9-wire connector and came up with nothing. I would recommend using a circuit tester, item # PTW2993, and wire by function only. Have a helper activate all of the various functions...
    view full answer...
  • Adapting 4-Pole Flat on Toyota Sienna to 5-Pole Flat Using Part # 20036
    To provide the converter you already have with a 5-pole connector, you have two choices. You can use and adapter, like part # 20036. The blue wire on the adapter would tap into the circuit that feeds the reverse lights on your Sienna. A more permanent solution is available. You can cut off the 4-pole connector on the vehicle, and wire in a 5-way flat vehicle end, part # HM37908. The brown, white, yellow and green wires would match those used by your existing connector. As with the adapter...
    view full answer...
  • Will the Curt 5-Way Mounting Bracket Work w/ the Hopkins Ergonomic 5-Way Flat?
    No, I am sorry it will not Keith. The Curt Mounting Bracket for 5-Way Flat Trailer Connector item # C58303 is designed for a standard 5-flat connector like item # HM37908. The grips and the cover on item # HM47890 aren't going to fit inside the space on that bracket. Instead you'll want to use the Curt Easy Mount Bracket for 4- or 5-Way Flat Trailer Connector item # C58001. This one mounts to your hitch receiver and sandwiches the connector into place so it'll have plenty of room. What...
    view full answer...
  • Connecting 4-Way From Bike Rack to 5-Way on 2010 Volkswagen Jetta SportWagen
    Hi Debbie; does your bike rack already have some kind of wiring harness on it? Typically a bike rack will have a 4-way installed when it has lights. The 4-way connector will actually be able to plug into the 5-way on your vehicle. If you only have loose wires you can add attach a 5-way to the bike rack wires using # HM37908. The blue reverse wire won't be used so you can cap it off.
    view full answer...
  • Wiring for Toyota 2010 Highlander with a 7-Way connector for Towing
    You will need the Curt Class III Round Tube Trailer Hitch, item # 13534, and with the tow package you will need the T-One Connector Wiring Harness with 4 Pole Trailer Connector - Toyota Highlander, item # 118449. I would go ahead and install the 7-Way connector. We have the Brake Controller 7 & 4 Way Installation Kit, item # ETBC7, which includes everything needed to install the wiring for the 7-way connector, once you have the 4-Way installed. You mentioned a 5-Way connector and if you...
    view full answer...
  • Electric Reverse Lockout is Not Working on a Boat Trailer
    First, make sure that your trailer has an electric reverse lockout, and that the 5th wire is connected to it and not something else. Then, on the vehicle side, check that the center pin wire is connected to a reverse light circuit behind one of the taillights on the vehicle. You can use a circuit tester like # PTW2993 if needed to make sure the center pin provides power when the vehicle is put in reverse. Then plug in the adapter you have and make sure that the pin that corresponds to...
    view full answer...
  • Connecting Harley Davidson 5 wire Harness to a 4 Flat Connector on a Trailer
    I would recommend you cut off the 5-way on your motorcycle. Wire in a tail light converter kit part # HM48895. This will convert your separate circuit tail light signal of your motorcycle to a combined circuit like what your trailer has. On Harleys the turn signal wire circuit is separate from the brake light circuit so a converter like the # HM48895 is needed to convert the signal into a combined circuit like what your trailer has. You will need a circuit tester like our part # PTW2993...
    view full answer...
  • Installing a 5-Way Flat Trailer Connector on a 2005 Toyota Tacoma
    The easiest thing to do would be to install Tow Ready Custom Fit Vehicle Wiring, # 118393, first. There is no splicing involved with this installation. The T-connectors plug in line with the taillight wiring. I have included a link to the installation details and a video showing a typical installation. After the harness is installed, you can install the 5-Flat Vehicle End, # HM37908. What you will need to do is cut off the 4-Way connector from the harness that was installed then splice...
    view full answer...
  • Troubleshooting Reverse Lockout Solenoid On Boat Trailer Not Allowing Trailer To Back Up
    You've wired the solenoid correct, so there are a few things to check. Do you have a 5-way or 7-way connector on your trailer and vehicle? You can't use a 4-way connector as you need an additional pin to go from the reverse lights of the vehicle to the solenoid. If you have a standard 4-way on the trailer and vehicle you'll need to replace the trailer end with the 5-way # HM37908 with the blue wire going to the solenoid, and adding the # C57187 to your vehicle. You will need a circuit...
    view full answer...
  • Trailer Wiring Diagram for 4-Way, 5-way, 6-Way and 7-Way Trialer Connectors
    A link to the trailer wiring you are asking about is provided, just scroll down the page to select the connector you have on your vehicle and trailer. The wires on the 5 pole flat are as follows White/ground, Brown/taillights, Yellow/left turn and stop, Green/right turn and stop and Blue/reverse lockout. The brown will run to both sides of the trailer and the yellow and green will only go to the respective side they are needed on. The Blue wire goes to the electric lockout solenoid for...
    view full answer...
  • Towing Motorcycle Trailer w/ 5-pin Trailer Connector Using Vehicle with 4-Pin Flat Trailer Connector
    A co-worker and I cobbled something together a few years ago that we called the Frankenadapter. It would consist of the # 118158 Vehicle to Vehicle Taillight Converter, a 4-pole trailer-side connector like # HM38168 and a 5 pin round vehicle side connector like # PK11502. The adapter would be constructed as shown in the provided photo. The 5 pin connector would connect to the wires shown to the right. The adapter will separate the stop lamp signal from the right and left turn signals so...
    view full answer...
    Image 1 for
  • Towing Motorcycle Trailer with 5-Wire Lighting System with Vehicle with 5-Pole Connector
    There are two good ways to accomplish this. You can convert the motorcycle trailer and the motorcycle to a combined system that uses the same light for the brake light and turn signals. The rear lamp assemblies would need to be replaced, and put a converter like part # 119178 on the motorcycle. This way, the trailer can easily be towed by the bike and the vehicle. The other method (which I would recommend) would involve constructing an adapter using the Vehicle to Vehicle Tail Light Converter,...
    view full answer...
    Image 1 for
  • Recommended 5-Pole Flat Trailer Connector To Replace Damaged Connector
    If the 5-way connector you have is installed on the vehicle you can use part # HM37908. You would just cut the connector off of your vehicle and splice the # HM37908 with the length of wire you need. You can use butt connectors like part # DW05744-5 to connect the wiring. If the connector is on the trailer then you can replace the damaged connector with part # HM47910.
    view full answer...
  • Troubleshooting Taillights with a 7-5-way Adapter on an Audi Q7
    The issue you are having is not a 4-5 way adapter issue. If everything was working correctly using a 4-way on a 5-way connector would work just fine. I would first just try pulling the adapter out and re-installing it just to see if maybe something is making good contact. If that does not fix it you will need to use a circuit tester like our part # PTW2993 to test for voltage first at the back of the 7-way on your Audi Q7. If there is voltage going into the connector but not out of it...
    view full answer...
  • Trailer Lights Only Work with Camper Plugged In To Shore Power
    It sounds like the trailer lights are tied into the interior lights and the trailer mounted battery and inverter. What I recommend is to have the trailer exterior lights bypass the rest of the wiring so that the trailer connector is isolated from the other lights. It seems that if everything is connected together through the battery or the inverter, including the trailer connector. Replacing the battery could solve the issue but I would still have the trailer connector separate from the...
    view full answer...
  • Will a Trailer 4-Way Plug Into a Vehicle 5-Way Without Adapter
    Yes, you can plug a trailer side 4-way trailer connector part # 002402 into a vehicle side 5-way connector part # HM37908 without any adapters needed.
    view full answer...
  • How To Connect Trailer With 5-way Connector to 6-way Round Connector On RV
    I have an option for you, but you will need to make the adapter as there is not a 6-way round to 5-way adapter available, or change the connector on your trailer to 6-way round. To make an adapter you will need the Pollak 6-Pole, Round Pin, Trailer Wiring Connector # PK11604 which will plug into the 6-way round connector in your trailer, then use the 5-Flat Vehicle End 5' Wiring Harness # HM37908 to connect to the 5-way connector on your trailer. The other option is to cut off the 5-way...
    view full answer...
    Image 1 for
  • Solution to Activate Reverse Lockout Solenoid of Surge Brake Trailer Being Towed with Front Hitch
    This is a really good question. Probably the best solution would be to wire a 5-way to the front of your truck like with the part # HM37908. Run the blue wire to your positive battery post and then the white to the ground and whenever it's plugged into your trailer the reverse lock out solenoid will activate and allow the trailer to move.
    view full answer...
  • Wiring Trailer Lights for 2009 Pontiac Vibe Without Using Converter
    Probably the easiest way to handle this situation would be to use a 5-way connector, part # 20017 for the trailer and part # HM37908 for the vehicle end. Use the extra wire for the brake light lead. If the trailer needs to be towed by another vehicle, simply use the 4 to 5 Way Adapter, part # 47515.
    view full answer...


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Info for this part was:

Employee Lindsey S
Edited by:
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Employee Michael H
Expert Research:
Michael H
Employee Jameson C
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Employee Jacob T
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Employee Cole B
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Employee Ryan G
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Employee Wilson B
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