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Adapter 7 Pole to 5 Pole Flat Wired Adapter

Adapter 7 Pole to 5 Pole Flat Wired Adapter

Item # A57WB
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Optronics 0 - 5 Feet Long Trailer Wiring - A57WB
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Great Prices for the best trailer wiring from Optronics. Adapter 7 Pole to 5 Pole Flat Wired Adapter part number A57WB can be ordered online at or call 1-800-940-8924 for expert service.
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  • Reviews (141)
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Optronics Trailer Wiring - A57WB

  • Wiring Adapters
  • Single-Function Adapter
  • 5 Flat
  • Plug and Lead
  • 0 - 5 Feet Long
  • Optronics
  • 7 Round - Blade

5-Way Flat to 7-Way RV Blade Adapter - Wired

This is an adapter that converts the tow vehicle's 7-way blade connector into a 5-way flat pin connector. This model has a short length of wire joining the two connectors.

  • 16" Long
  • Converts a 7-way blade connector into a 5-way flat pin connector

A57WB Adapter 7 Pole to 5 Pole Flat Wired Adapter

Alternate part number: A-57WB

California residents: click here

Video of Adapter 7 Pole to 5 Pole Flat Wired Adapter

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

Video Transcript for Optronics 7 Pole to 5 Pole Flat Wired Adapter Review

Randy: Hey guys, it's Randy here at Oftentimes, our customers ask us for a solution to turn their regular working seven pole on the back of their vehicle into either a four pole or five pole flat. This is one of many options that we have here at etrailer. This one's from Optronics. Now, unlike a lot of the other ones that we have like this where the plugs are mounted pretty much right here on the back side of the plug, this is also going to give us an extension. Now, this is about 21 inches from this tab right here which is going to be about midway on your door to the end of the plug there, just to give you an idea.

It's going to give you a nice, long reach. This can be really important if the trailer that you are using has a short pigtail on it.If your plug, like on a Trailblazer, or a Toyota 4Runner, if it's way up underneath here and you need to get some reach back, or in lifted applications. A lot of times, you're going to have in a lifted truck, you're going to have a pretty deep drop, and the longer those get, the more and more length we need to get from our connector to the trailer.Now, basic four pole functions are going to be running lights, ground, left turn signal and brake, and right turn signal and brake. The fifth one that we have here, that's used a lot of times in marine trailer applications. That's your reverse signal.

As you shift your vehicle in reverse, that's going to send power through, and that can prevent a surge coupler from locking up. So as you're trying to back up, it'll back up smoothly. But customers also ask frequently if they can power some trailer lights off of it, if they can power some backup light. So as you get to your destination, you throw it in reverse, you'll have a lot of light behind you to see, and that's perfectly acceptable.Now, other than the extension portion of this, I think this is a really, really rugged adapter. Everything has been molded on, so we don't have any gaps in it anywhere.

This isn't going to be something that we have any concern about it over time, water seeping into it and causing us issues. I really like the way it's designed. It feels really good. If I had a need for this, then I would definitely own it, whether it was a short pigtail or if I had a lifted truck and I needed to get a little bit more reach. I do have a Trailblazer, and this would come in handy when I plug it underneath there.

I actually made my own. I didn't know this one existed or I would've just bought this one. It would've been easier.Now, as far as the installation process goes, it's no different than a standard seven pole. You're just going to slide this in so that the catch on the door fits in behind this tab. It's going to keep it nice and secured, prevent it from coming out. Then on the other end, we're just going to plug in our trailer. Now, one little tip; if your four pole connector is shielded, meaning that these pins are inside of a large, black plastic cover or that they don't stick out like what you see here, using that in a four pole application will require you to trim just the end of it off. You can see as this goes in, if that shield was in the way, it wouldn't allow it to slide down inaudible 00:03:12. So you might have to recess it for that. But as you can see, it's an excellent solution. It's going to give us the extension we need, be able to power a trailer and keep us safe.If this plug we're not to reach the back of your truck, or if you didn't have a working seven pole, with short distances, a lot of people just leave it off, and that makes a dangerous situation for us. Being able to see what a trailer's doing in front of you makes the experience a lot better. For anybody driving behind you, they know if you're stopping or if you're turning, so it is important.As far as customer reviews go, it gets really, really high reviews and kind of some of the things I said, just how sturdy and how good quality it feels is really important. Some of these adapters can sometimes feel a little bit more flimsy. Although they do the job really well, they just don't feel as high a quality as what we have here. Now, with any plugs like this, we always recommend dielectric grease. This is available on our website if you don't have it. Just want to put it on each of the connection points there. That's going to keep moisture out. We don't have any moisture in there, we don't have dirt holding, we're not going to have any corrosion.The one slight dig, I guess, I would have on it, you can see that our connectors on this side are brass. Those tend to corrode a little bit more quickly than what we get out of a nickel coated style. But I think all in all, you put a little dielectric grease in here, this is going to solve a lot of problems for you.

Customer Satisfaction Score:

Customer Reviews

Adapter 7 Pole to 5 Pole Flat Wired Adapter - A57WB

Average Customer Rating:  4.9 out of 5 stars   (141 Customer Reviews)


Nice adapter for my rv to motorcycle trailer. Easy to use and works great.


Well made. Great extension from truck to my boat. Adds an additional 20" of wiring


Great Service!


Flawless, great quality.


This is a somewhat unusual and hard to find item at most stores selling automotive trailer wiring accessories and harnesses. I purchased a new 4X4 pickup which has the 7-blade connector to the left side of the license plate holder on the rear bumper step. Previously, I had my 7-blade connector immediately adjacent to my receiver housing on the underside of my rear bumper. And, with the higher profile of the 4X4, I now use a 3 1/2" drop drawbar to mount my 2" ball. This new arrangement puts my boat trailer harness extended to it's maximum, with minimal room for wide, short turns over a small distance, or backing up at sharp angles. Enter this Optronics adapter, which adds another 18" to the pigtail side of my trailer wiring, and provides only a single connection between the two five way flat connectors. Molded in 7-blade plug and solid jacketed 12Ga wiring with the five way flat female connector molded in on the other side. This adapter works like a champ and looks great!

Chris W.


This adapter has been in use about 150 days over the past year and performs without any problems. Connections remain tight and waterproof, and we have certainly found ourselves having to tow in some extremely wet weather conditions last year. Although this is an economy-rated product compared to some others you have available, I could not see needing a better adapter/extension than this one by Optronics.


Purchased a 2023 4Runner. The way the plug in for my boat trailer is recessed my cord would pull out when I made a turn. This extension is just what I needed. Also its heavy duty in construction.


I needed this to hook up my new 5 pin trailer with surge brakes to my truck with a 7 pin plug. Not only does it allow me to back up and release the brakes but my trailer assist feature now works with the back up camera.



After a year its working just fine. Very happy with this purchase.


I was unable to find this wiring harness at any of the local automotive or farm supply stores. It is exactly what I needed for my boat trailer and the product works great. Once I ordered the product, it arrived at my house within days, which is great service on top of a solid product.



Still very happy with the wire harness. Thanks for following up this isextraordinary customer service ...


The light and rubber boot was easy to put in a worked well, but the boot did not fit as tight as I would have liked when the trailer was empty and bounce a lot the boot and light fell out, have reorder a new boot and light will put silicone on the boot this time



Great when I reordered the second time I put silicone around the rubber seal and then put in the light as worked perfectly


Used the adapter multiple times! Not much to say except works great! Extremely satisfied. I can however not say enough about etrailer's customer service. They are awesome plain and simple. Thanks for following up to see how I liked the adapter!

Mike S.


Product works great! Extremely satisifed.


This adapter is made out of quality material. It was a perfect fit on my Envoy, and boat trailer. I would recommend this item to anyone who is in need of this type of adapter.

Frank F.


After using this adapter for a year, it still works great. I have had no problems.,


Some of the smaller trailers I haul from time to time do not have a harness long enough to reach all the way to the bumper of my 3/4 ton pickup. This pigtail perfectly solves that problem, without adding too much excess wiring. It includes the fifth pole for some boat trailers to release the pressure brakes while in reverse.


First time using this device it would help to include some general directions to help new users like myself. Had to call etrailer for additional information on this adapter. This did help answer the question I had. Thanks Quinn, I believe is the one that helped.

Etrailer Expert

Jenny N.


I recommend watching the video review that I have linked below.


Bought this “connector” for the purpose of providing my vehicle’s tail light signals to my boat trailer’s
tail lights and turn signals. The connector that I received from ETRAILER is of high quality and exactly
what I needed to accomplish my intended purpose. Very happy with this product.


Makes using a different hitch a breeze. As sometimes you need more drop and setback which shortens the harness.



Very pleased with product well made


The 7-way blade to 5 pin adapter is terrific. The quality of the connector's sockets and ground pin are excellent. Likewise, the outer jacket and molded connectors make the adapter nearly impervious to environmental induced deterioration.


I love this thing! The best part is the cable length. I was needing to either splice into the trailer's wiring and extend it or create a foot long extension. This did it for me! I am going to show it to our local trailer manufacturer.


This extension was exactly what I needed to hook up my Ranger Bass Boat to other's trucks where the original trailer lights are not long enough. Great product and price.


I re-wired my boat trailer and up-dated my lights with these things.. great products worked better than I thought !


Although I have yet to use it,this is exactly what I needed for my new to me rig. 5 pin trailer side plugs aren't easy to find but this one does it all,quality made, at a good price and fast shipping.


Order arrived as promised, hooked it up to my Tundra and it work flawlessly. If you needed the extra extension like I do, this is it. The adapter feels very sturdy and I think it's going to last a long time. Definitely will do business with etrailer again, you guys are awesome.




The order was as 7 to 5 way trailer wiring adapter.It seems well made and I would expect it to hold up well. What really stands out is how quickly it arrived all the way here in Ak ,during the Covid outbreak when most others have slowed to a crawl. 3 days!


This is just what we need, a sturdy 7 to 5 pole adapter that is long enough to connect to the wiring of our boat trailer. In addition, we received it promptly.


This is the best .. I need it for my 4runner to back the boat up to release the brakes the trailer plug on the rig is 16inches of center not like my tahoe.


Excellent product and super fast delive ry

Show More Reviews

See what our Experts say about this Optronics Trailer Wiring

  • How Many Circuits are Supported by the Optronics 7 Pole to 5 Pole Flat Wired Adapter # A57WB
    Thank you for your recent purchases from etrailer. The Optronics 7 Pole to 5 Pole Flat Wired Adapter # A57WB that you purchased is intended to allow a tow vehicle with an RV-style 7-way blade type trailer socket to connect to a trailer that uses a 5-pole flat type connector. The linked article on trailer wiring shows these and other connector types commonly in use. The 5th wire on a typical 5-pole trailer is usually blue in color and is there to carry signals for electric trailer brakes....
    view full answer...
  • Is Optronics 7 Pole to 5 Pole Flat Wired Adapter Waterproof
    For something to be considered waterproof it has to be able to be submerged under water for a certain amount of time and not let any water in. Based on that the Optronics adapter # A57WB is not technically waterproof. But at the same time you should unplug the trailer from the tow vehicle prior to submerging the trailer in the water so as to eliminate any chance of a short caused by water. Using dielectric grease, # 11755, on the trailer connectors/adapter will repel moisture and would...
    view full answer...
  • Recommendations For 7-Way to 5-Way Trailer Wire Adapters
    You can install a 7-way trailer plug on the trailer and only wire the 5 circuits you need based on our FAQ page on wiring, which I have provided a link to. If you go this route, you will need to trace each circuit on the trailer to determine its function and then wire it to the plug accordingly. I have provided a graphic showing the function of each individual circuit on the 7-way trailer plug. You also might need a new adapter to connect your 7-way plug on your vehicle to the 5-way plug...
    view full answer...
    Image 1 for
  • Availability of 32 Inch Long 7-Way to 5-Pole Trailer Connector Adapter
    The Hopkins Heavy Duty Coiled Trailer Connector Adapter, part # HM47075 should fit your needs very nicely. When stretched, the cable measures 36 inches long. If you were looking for something that did not have a coiled cord, an adapter could be constructed using a 7-way vehicle end plug, part # PK12706 and a 5-pole vehicle end, part # 20016. You could also use a 3 foot length of wire loom, part # 459075-1 (sold by the foot) for a neater appearance.
    view full answer...
  • Recommended 7-Way to 4-Way Cord for Trailer
    It looks like you purchased the # A57WB, and most standard 4-Pole flat connectors will fit this 5-Pole flat connector- so you may just be able to plug it in not using the end port. However, you could also just get a new cord with a 4 flat on it with the Hopkins Heavy-Duty Trailer Coiled Wire Adapter for 7-Way to 4-Wire Flat # HM47065.
    view full answer...
  • Tail Lights on 1992 Ford F-150 Stay On When Connected To Boat Trailer With 7-Way to 5-Flat Adapter
    If I understand correctly, the taillights on your 1992 Ford F-150 stay on when you connect your boat trailer to your truck using a 7-way to 5-flat adapter and when the brakes are applied the vehicle taillights go out. It sounds to me like power is somehow feeding back to the taillight circuits on your truck and there is a short somewhere. To troubleshoot this issue, I would start at the 7-pin connector on your truck with the adapter and boat trailer disconnected. Make sure the connector...
    view full answer...
  • Will Optronics 7-Way To 5-Way Adapter Replace Pollak Adapter
    You will want to check the style pins on your adapter you currently have to make sure you get the correct style. The Optronics 7 Pole to 5 Pole Flat Wired Adapter, part # A57WB, is designed to fit a blade-style connector. The adapter converts a 7-way connector and gives you a 5-way flat connector, and is 16 inches long.
    view full answer...
  • Adapting 5 Pole Trailer Connector to 7-Way Connector on Truck
    A boat trailer with a 5 pin flat trailer connector on it would typically be equipped with hydraulic surge brakes. The extra pin controls an electric lockout solenoid on the surge coupler that prevents the brakes from actuating when the trailer is backed up. The center pin on the truck's 7-way should be tapped into the truck's reverse lamp circuit, so that the pin gets voltage when the transmission is shifted into reverse. If the adapter you spoke of is like the part # A57WB we offer, then...
    view full answer...
  • Recommendation for a 4-Way Flat to 5-Way Flat Adapter for a Boat Trailer
    We do have an adapter to go from a 4-Way on a vehicle to a 5-Way on a trailer. You can use # 20036. The extra blue wire will get wired into the reverse light circuit on the vehicle. The 5th wire on a boat trailer 5-Way is usually for an electric reverse lockout. When the vehicle is placed in reverse it sends a signal back to a solenoid on the actuator and does not allow the brakes to engage.
    view full answer...
  • Recommended Wiring To Make 2011 Honda Pilot Compatible With 5-Way Trailer Wiring Reverse Solenoid
    For your 2011 Honda Pilot, I recommend you use the Honda Replacement OEM Tow Package Wiring (7-Way) w/ Circuit Protected ModuLite HD Module # 118253 so you will also have the reverse function you need. This will require you to use the Draw-Tite 6 and 7-Way Trailer Connector Mounting Box # 18159. Then you will need an adapter like # C35FR or # A57WB. With trailer connectors, it is wise to use dielectric grease like # 11755 to keep moisture and debris out of your connections.
    view full answer...
  • Length of 7-Way Connector Used on Optronics A57WB 7-Way to 5-Pole Trailer Connector Adapter
    The 7-way plug portion of the # A57WB 7-way to 5-pole adapter measures 3 inches, as shown in the photo I edited for you.
    view full answer...
    Image 1 for
  • Recommended Adapter to Convert 7-Way Blade Connector to 5-Pole Flat Connector
    We offer a range of trailer wiring adapters to let you join a vehicle with one connector type to a trailer with a different connector. The link provided will show you all options for adapters that convert from a 7-way blade-style connector to a 5-pole flat style connector. You can use a non-wired plug-type adapter like Optronics # A75TB, or if you prefer a wired-type adapter to give you a bit of slack you can use Optronics' 16-inch adapter # A57WB. For a heavy-duty coiled adapter you might...
    view full answer...
  • Can One Of The Five Wires On A 5-Way Trailer Connector Be Used For Backup Lights On A Trailer
    The 5-way flat trailer connector is most commonly found on boat trailers that have hydraulic brakes. The fifth wire is hooked up to the reverse light circuit on the vehicle which then sends a signal to the hydraulic coupler to disengage the trailer brakes when the vehicle is put in reverse. If you are not going to use the fifth wire on the 5-way to disengage your brakes on your trailer you could run the fifth wire on your trailer connector to the backup lights on the trailer. You will...
    view full answer...
  • Will a 4-Pole Flat Trailer Connector also Fit this 5-Pole Flat
    Most standard 4-Pole flat connectors will fit this 5-Pole flat connector. There are quite a few options as far as adapters that you could use. I have added a link to all the 7-Pole to 4-Pole adapters we have. One in particular has both 4-Pole and 5-Pole connectors, part # 37385. We also have a coiled version of the part you were looking at, part # HM47075.
    view full answer...
  • Will Trailer Connector Provided With Stealth Hitch SH25VR Release Surge Brakes On Boat Trailer
    If your surge brake coupler is equipped with an electric lockout solenoid, the 7-way trailer connector included with the Stealth Hitch # SH25VR will actuate the lockout, as long as the purple wire for the 7-way is tapped into the vehicle's reverse lamp circuit as outlined in the linked installation instructions. This assumes your boat trailer uses a 7-way trailer connector. If the trailer use a 5-pole connector, you can use an adapter like part # A57WB. I'll also link to an installation...
    view full answer...
  • Adapter Needed to Use a 4-Way or 5-Way Trailer Connector with a Factory 7-Way Socket
    There are a couple of ways you could attach a 4-way or 5-way connector to your factory 7-way connector on your 2004 Chevrolet Avalanche. If you wanted to have the option to use both a 4-way and 5-way connector without having to keep track of multiple items, then you may want to check out the Hopkins 7 Pole to 4 Pole and 5 Pole Adapter, # 37385. This adapter will insert into the 7-way socket on your vehicle and has connections for a 4-way and a 5-way trailer connector. If you only wanted...
    view full answer...
  • Will Optronics A57WB 7-Way to 5-Pole Trailer Connector Adapter Work With a 4-Pole Trailer Connector
    The 5-pole end on the Optronics # A57WB 7-way to 5-pole trailer connector adapter will work with most trailer side 4-pole connector such as you describe. Some 4 pole connectors have a plastic shroud around the 3 exposed pins. You'd simply need to cut that away with a sharp utility knife, and it'll work just fine.
    view full answer...
  • Could 5-Way of 5-Way to 7-Way Adapter be Removed and Wired to Trailer Wiring
    Yes, if you wanted to just remove the 5-pin on your trailer as well as on your adapter you could wire the 7-way left over to the wiring of the trailer. If the colors are the same on the trailer wiring side as what the pins correspond to on the adapter's wiring then you could match them color by color.
    view full answer...
  • Replacement Actuator With Electric Lockout for Fulton A60
    What you need is an actuator rated for disc brakes with an electric lockout. I recommend the Demco Hydraulic Brake Actuator # DM62VR.This has a 7,000 lb capacity which is slightly higher than your A60 and fits a 2" ball. It also features the E-Z latch coupler that lets you drop the coupler over the ball to snap in place. The electric lockout will allow you to back up without getting out of your truck. I'm assuming you currently have a 4-way on your trailer so you will also need to change...
    view full answer...
  • Using 4 to 5-Pole Trailer Connector Adapter # 20036 for Towing Boat w/ 2011 Toyota Highlander
    The extra pin on your boat trailer's connector is most likely a reverse lock-out for your surge or hydraulic trailer coupler. The extra circuit is tied into the reverse light circuit of your vehicle. When the vehicle transmission is shifted into reverse, the reverse light circuit energizes and activates a solenoid in your coupler, which allows you to back the trailer without the brakes applying. We do indeed have an adapter that would work for you, part # 20036. The extra blue wire on...
    view full answer...
  • Can Trailer be Wired for Backup Lights Using 5-Way Plug and then Converted to 7-Way
    Yes, you could wire your trailer to have backup lights by using a 5-way flat like the Hopkins Endurance Trailer Connector, # HM47910, and then use an adapter like the 7 Pole to 5 Pole Flat Wired Adapter, # A57WB, to be able to plug in to your vehicle's 7-way. Although wiring the 5-way connector for backup lights and then converting to the 7-way will work, this will require more parts than what is necessary. I recommend just wiring in a 7-way connector like the Pollak Black Plastic, 7-Pole,...
    view full answer...

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