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Adapter 4 Pole to 7 Pole Vehicle End Trailer Connector

Adapter 4 Pole to 7 Pole Vehicle End Trailer Connector

Our Price: $33.33
Trailer Wiring
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Shipping Weight: 0.57 lbs
30717 - 4 Flat Tow Ready Wiring Adapters
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Great Prices for the best trailer wiring from Tow Ready. Adapter 4 Pole to 7 Pole Vehicle End Trailer Connector part number 30717 can be ordered online at or call 1-833-496-1390 for expert service.
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  • Reviews (573)
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Tow Ready Trailer Wiring

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

  • Adapter converts from 4 pole wiring on vehicle to 7 pole round plug
  • Additional wire leads for brake, power and accessory are 12" long
  • Mounting bracket (18138) is sold separately

Wiring diagram

Product detail

20321 Adapter 4 Pole to 7 Pole Vehicle End Trailer Connector

Item # 30717

California residents: click here

Video of Adapter 4 Pole to 7 Pole Vehicle End Trailer Connector

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

Video Transcript for Tow Ready Wiring - Wiring Adapters - 30717 Review

Customer Satisfaction Score:

Customer Reviews

Adapter 4 Pole to 7 Pole Vehicle End Trailer Connector - 30717

Average Customer Rating:  4.8 out of 5 stars   (573 Customer Reviews)


Super Service at ETrailer - I have never had an issue with the help provided or with any product

Was easy to install. Fit perfect. Has stayed looking great. It is great having a mounting bracket for the electrical hookups. It keeps the 7pin more out of the way and more solid.
Paul - 10/05/2022


Every phone encounter I’ve had with etrailer has been excellent. Their staff on the phones know their stuff and they have most every rv/trailer accessory known to man. The seven pole side is much more robust than the four pole side, which I leave connected all of the time. Problem solved


This product works as expected. There is not too much to the installation, just plug it in properly and mount the ground wire.
I did not find an easy way to mount this to my wife's Odyssey, or to the trailer hitch (item# 75270). Luckily, I do prototype design and manufacturing. So I came up with my own solution. I designed and made my own bracket to mount the 7 pole to the trailer hitch. It works like a charm, and looks great!


i had to replace these two items as my dear daughter went down our goat path driveway too fast. they replaced the originals from etrailer from the prior year. shipping is timely and customer service actually helps! i wired from battery to controller to hitch myself, and everything fit.


Average quality part, would be nice to include a mount but ended up going the extra mile and used a hole saw to install it in my van’s bumper out of harms way. Would be easily damaged if mounted near the hitch.

Item # 18138
Mounting Bracket for 7-Way
is the mounting bracket that works with this wiring.
-- Etrailer Expert Sierra K - 12/01/2021


This was perfect for my needs. Good quality too.

The product is working out great. I have not had any issues with it.
Teo - 10/10/2022


this connector along with the short L bracket and the mount bracket- gave me a nice connector to my hitch.
Though I used the short connector and did have to slightly bend it to allow the 4 to 7 pole connector to fit.

If Id bought the long L bracket-- It could have worked-- but bending a little worked well.


I was really skeptical about this adapter but for no reason! Installed in about 10 minutes using etrailer mounting bracket, dielectric grease, a couple zip ties, and some electric tape. Worked perfectly the first time I tested it on my trailer.


I really appreciate you following up on my order. The information and videos will help when I drop the harness and circuit breaker off at my local shop. When I went to them originally with my problem I couldn't answer all their questions. With the parts in hand they should be able to convert my four prong to the seven prong plug used on my new trailer. Thanks also to Craig at CampInn for directing me to your site and the parts they are using in the construction of my trailer.


Works great. Easy install.

more sensitive to dirt than I expected, but that might be common to all trailer connections, I don't know. I noticed on a trip that my brake controller said NC (no connection), and I didn't have trailer brakes, which meant my blinkers probably hadn't been working, either. I got pretty worried, and looked at it and only saw just a little black gunk on one blade. But cleaning that small amount of black gunk off solved the problem.

So far, so good!

Thanks for your business and your review, Zach! Using dielectric grease like 11755 on your connections increases reliability and the life of the connection by preventing corrosion and sealing the connection.
-- Etrailer Expert Laura E - 02/10/2017


Perfect fit, great quality product and it was easy to install!


Installed the wiring harness for 2021 Toyota Tacoma. Everything went together just as noted in the instruction.


Joe at etrailer was able to provide this solution and saved me literally hundreds of dollars to have a reputable place put in a new harness onto my AWD MKX. Thank you!


There was no splicing wires, it was plug-and-play, highly recommended, very easy installation


Every time etrailer has provided me with the needed wiring!


Had a great experience ordering from etrailer.
arrived fast and customer service was excellent.


I bought this because I hated the flat four pole that just hung over the bumper. Drilled a 1 7/8 inch hole in my bumper with bimetal hole saw. Mounted nice and clean. Be sure to hook up the White ground wire to your frame. The ground wire from the flat four does not pass thru this connector. Also if need be you can still pull a trailer with a flat four pole just by unpluging it

It’s a year later. Still working great no problems
Carl m - 01/13/2019


Kyle was extremely helpful in not only finding the right hitch but the accessories I needed to go with it. Would definitely recommend to all my friends. Prices were excellent too!


This 7 point harness wired right in with my T1 connector and is great for hooking up to my camper, very easy to install!


This is a great product . The price was $18.00 dollars cheaper than some I found online. I have a 2002 dodge ram 1500 pickup, this adapter will change the 4 pole( which is made on my truck) to a 7 pole( which is on the trailer I will be using). The product connected, and bolted up to my truck bumper very easy. E trailer is the best.

Im still enjoying this product, Ive used it several times, still workingwell
Rics49 - 04/06/2015


I wanted to show the custom installation. I did not want it under the bumper


Worked as intended - wished they included a wiring diagram for us trailer newbies.


I was surprised how fast the shipping was and the price for the product was very reasonable. I did not mind that there was no mounting plate for the adapter because I wanted something that would hook up to the camper when I need to use it and then take it off afterwards. I know I will be coming to etrailer for any other trailer or camper needs that may come up.

could not be happier with the purchase that I made
Al N - 05/26/2016


Has been working great since purchased and installed 3 months ago. Used for several different trailers and long distance trips. Easy to install. Had to be slightly creative with the attachment of the ground. Did not see a reason to have a ground on this portion since everything else is already grounded, however would not work without grounding to the frame. Only used the four way connection and taped remaining three back. Hope for good things to come with this produce. Highly recommend this product.

Had the same issue with the ground kurt. Almost gave up on it until I read your post. Thanks.
-- comment by: mike g - 06/17/2014
Thank you so much. Ours wasnt working either until we grounded it to car frame.
-- comment by: Sarah - 10/08/2015


Hitch was as advertised. The printed instructions made it a breeze. Took about an hour with me and an experienced mechanic. The light kit took a little longer than expected but was installed inside the car vice behind the lights like the video showed. Towing a camper this weekend, not expecting any issues.

All is well. Don’t use it that often but when I needed it they’ve been there. I’ll use etrailer from now on.
B K - 08/10/2018

Show More Reviews

See what our Experts say about this Tow Ready Trailer Wiring

  • 7-Way Wire Color Functions for Adapter 4 Pole to 7 Pole Vehicle End Trailer Connector, # 30717
    You are correct. The white wire is grounded to the frame, the black wire runs to the battery, and the blue wire is run to your trailer brake controller. The yellow wire is an auxiliary wire, and can be used for whatever extra purpose you need it for. If you have reverse lights on your trailer or hydraulic surge brakes with reverse lockout, you can splice the yellow wire into your vehicle reverse lights or to the lockout. I have posted links to our wiring help pages for you to review.
    view full answer...
  • 4 Pole to 7 Pole Vehicle End Trailer Connector 30717 Yellow Wire
    The yellow wire on the Adapter 4 Pole to 7 Pole Vehicle End Trailer Connector, part # 30717 can be used as an auxiliary wire. Some people will use it to light the reverse lights on their trailer, as a reverse lockout circuit or maybe to power a break-away kit. If you do not have a need for the additional source, the wire can be grounded with your ground wire.
    view full answer...
  • 4-Way to 7-Way Wiring Adapter
    I would recommend the 4-way to 7-way Adapter, part # 30717. Keep in mind that although you will have lighting functions, the electric trailer brakes will not work unless the lead on the adapter for the brake output is installed to a brake controller.
    view full answer...
  • Adapter 4 Pole to 7 Pole Vehicle End Trailer Connector Instructions
    Sorry about that, I'll be happy to help! When connecting the adapter, (4 Pole to 7 Pole Vehicle End Trailer Connector), the white wire is your ground wire, the black is the hot wire to the 12V, the blue wire is to the electric brakes, and the yellow wire is for reverse. The 4 pole just plugs into the existing 4 pole.
    view full answer...
  • 4 pole to 7 adapter 2008 Toyota Sienna
    The ground (white wire) definitely needs to be hooked up for your vehicle to power the lights on the trailer. You need to make sure the ground is mounted to a clean metal surface for a good connection. The black wire does not need to be hooked up if you do not have brakes or a battery to be charged while towing. Usually the extra black wire is for charging the trailer battery, the blue wire is for brakes and the heavy yellow wire is for auxilary power. You do not need to hook these...
    view full answer...
  • 4-Pole to 7-Pole Vehicle End Trailer Connector for Coleman Pop-up Camper
    I am sorry, we do not have a wiring diagram for this particular part, however we do have a Wiring FAQ that can help. I have included a link to it below. The white wire on the 4-pole connector is not active because the loose white wire overrides it. So the white wire coming off the adapter needs to be grounded. The 4-pole plug on the adapter needs to be plugged into the original 4-pole plug on the vehicle.
    view full answer...
  • What wires on the Adapter 4 Pole to 7-Way and 4 Pole are Used for What Functions
    You are right the blue wire is usually for electric trailer brakes and runs to the blue wire on the brake controller. In some cases the blue wire is wired to the backup light circuit to disengage hydraulic surge brakes when backing. The black wire is normally used for accessory power and the yellow wire is auxiliary power that is used to charge the battery.
    view full answer...
  • How and Where to Wire the Four Loose Wires on the 4 Pole to 7 Pole Adapter, part # 30717
    The white wire is a ground and should be attached to the frame. The blue wire goes up to the blue wire on the brake controller. The black wire is a 12 volt power wire and is connected to the car battery. The orange or yellow wire can serve a few functions. It can be a reverse lockout for hydraulic brakes, it can be an auxiliary power supply, it can be used for reverse lights on a trailer, or if not needed, it can be taped out of the way. I attached an FAQ page on brake controller wiring...
    view full answer...
  • Where Do the Black and Blue Wires on 30717 Attach To on a 1999 Ford F-250
    If your truck has the brake controller port underneath the dash, then there will be some wiring towards the rear of the truck that you will need to splice into. The blue wire on part # 30717 needs to be spliced into the blue wire on the factory tow wiring. We have an instructional page that shows how this is done that I have linked to below. You can also splice the black wire on the 30717 into the orange wire on the truck for a 12V power source.
    view full answer...
  • Where Does the Black Wire Attach for Harness 30717 on a 2003 Chrysler Town and Country
    The black 12 volt lead on Adapter 4 Pole to 7 Pole Vehicle End Trailer Connector, # 30717, attaches directly to the battery on your 2003 Chrysler Town and Country. You will have to attach the black wire to a length of additional wire, like 10 Gauge Blue Primary Wire - per foot, # 10-1-1, under your vehicle and run that wire to the battery through a 40 amp circuit breaker, # PK54540.
    view full answer...
  • Can the 7-Way Adapter part # 30717 be Used by Just Plugging in the 4-Way
    If you do not need the additional functions beyond the trailer lighting functions that a 4-way carries you can use the part # 30717 by just plugging in the 4-way to it and you would be ready to go. You would want to tape up the additional wires up and out of the way.
    view full answer...
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  • Troubleshooting Trailer Wiring that Stops Working When Headlights are Turned On
    Try improving the connection of the main ground wire of the trailer wiring harness. Make sure it is attached to a clean metal surface. Or you can run all of the trailer wires back to the main ground. This is actually the ideal solution. But you can also check the current grounds for the lights to make sure they are making a solid connection to a clean metal surface. What you described is the classic insufficient ground scenario so finding a way to improve the grounds will fix the problem.
    view full answer...
  • Trailer Lights are Not Working with 4-Way to 7-Way Adapter Plugged Into 2011 Ford Escape
    For the adapter # 30717 to function, the white wire has to be grounded to the vehicle frame. Without that ground it will not function. If it is properly grounded and you still do not have lights on the trailer, make sure that the adapter 7-Way and the trailer 7-Way pin configurations match up. I have included a link to our wiring FAQ article that shows diagrams of how various connectors should be pinned. If you are still not getting lights test the 4-Way on the vehicle with a circuit...
    view full answer...
  • What are the Functions of a 4-Way Trailer Connector
    Trailers use a combined brake and tail light circuit (2-wire system). The left brake light and turn signal is with the yellow wire and the right brake light and turn signal is with the green wire. I have included a link to our FAQ on wiring for you that shows the functions.
    view full answer...
  • Left Turn and Brake Signal Does Not Work Using the Adapter 4 Pole and 7 Pole Connector # 30717
    The first thing that you will want to do is to use a circuit tester like Quickee Circuit Tester, # 3808, to test the pins for proper function at the 7-way connector, # 30717, that you just installed. I would recommend testing each pin for proper function. When looking at the 7-way connector, the drivers side brake and turn signal, or brake and left turn signal, pin should be the pin in the 9 o clock position. If all of the pins on the 7-way connector function appropriately, then you know...
    view full answer...
  • Dim and Malfunctioning Trailer Lights on a Trailer Towed by a 1988 Chevy C/K Series Truck
    This sounds like a weak ground, corroded connector, or both. Make sure that the ground on the 7-Way you installed is attached to a clean and corrosion free bare metal surface. A weak ground could cause this issue. Ground problems normally show up when there is more load on the system like when the running lights are on and you step on the brake. Also make sure the 4-way that you installed is properly grounded. A corroded connector can cause all sorts of weird things to occur as well so...
    view full answer...
  • Finding a Ground Location for a Trailer Wiring Harness on a Kia Optima
    You may need to scrape away some undercoating on the bottom of the vehicle in order to get a bare metal surface. Any surface with coating or paint will need to have those materials removed in order to get a good ground connection. Usually behind a tail light assembly there is some bare metal. You can also look for other wiring harnesses nearby and ground it in the same location.
    view full answer...
  • Troubleshooting a 2006 Chevy Silverado 12 Volt Trailer Connector Circuit
    It sounds like the 12 volt circuit has not been completed under the hood of your 2006 Chevy Silverado. Check out the FAQ article I attached that shows where this connection is made so that you can check there. You may find that the connection is made but the fuse is blown, so check and replace that as necessary.
    view full answer...
  • Does Every Wire of the Adapter 4 Pole to 7 Pole # 30717 Have to Be Run
    The yellow wire of the 7-way adapter part # 30717 is an aux. circuit that typically gets used for reverse lights. If you have no use for that circuit you would not have to hook it up. You could then just tape it up and out of the way.
    view full answer...
  • Will Camper Fridge Drawing Power from Hybrid Battery Damage the Battery on a 2007 Toyota Highlander
    If the 12 volt circuit on the 7-Way is connected to the main hybrid battery that powers the drive wheels on your 2007 Toyota Highlander then you would need to be careful about how much power items are pulling from it. Things with low power draw such as LED lights are not going to be an issue. But a refrigerator compressor can use a lot of amperage and that could potentially be harmful to a hybrid battery. What I recommend is to have the 12 volt circuit from the 7-Way just go to the trailer...
    view full answer...
  • Troubleshooting Running Lights That Go Out When Brake Lights Are Activated
    It sounds like you may have a weak ground connection on your vehicle's trailer wiring harness. A bad ground can cause all sorts of odd effects, including having one light function go out when another is activated. A weak ground will pass enough current for some functions to work, but possibly not for others. Check that the wiring harness ground wire's ring terminal is tightly attached at a clean bare metal surface on the vehicle. You may want to clean/sand that spot to ensure metal-to-metal...
    view full answer...
  • Will 2014 Hyundai Santa Fe 4-Way Connector Provide Charge to Trailer Battery Through 7-Way Connector
    Running a 12 volt power circuit on your 2014 Hyundai Santa Fe would allow you to maintain the trailer battery but would not provide a way to charge the battery. As for the 4-way, this will only provide power for the lights and signals on your trailer. In order to actually charge the battery you will want to use a battery charger connected to a 110 outlet.
    view full answer...
  • Trailer Running Lights Not Working when Connected to 4-Way on 4 and 7-Way Trailer Connector
    The trailer connector you are using on the vehicle needs to be grounded and the connector on the trailer has to be grounded as well. All of the lights also need to be grounded. This does sound like a ground issue. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside...
    view full answer...
  • 4-Way to 7-Way Adapter Recommendation for Towing Pop Up Camper
    Most likely what you would need is the part # 30717. This has a 4-way on one side of the connector that would get plugged into your Explorer and 7-way connector on the other side for connecting to your trailer. This 7-way is a 7-way blade style connector which is different from a 7-way round, but since the overall shape of the connector is round the terms get confused frequently. Since a 7-way round is typically found on heavy duty trailers, and RV style trailer almost always have a 7-way...
    view full answer...
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