What is the Difference Between a 4-Way and 7-Way Trailer Connector

Question

Question:

What is difference between a 4 pin and 7 pin trailer connector?

asked by: Carl Z

0

Expert Reply:

A 4-Way trailer connector has the basic lighting functions only; running lights, left turn signal and brake lights, right turn signal and brake lights, and ground.

A 7-Way has these functions and a 12 volt circuit, a circuit for electric trailer brakes (requires a brake controller in the vehicle), and a reverse light or auxiliary power circuit.

There are other types of connectors as well. I have included a link to our help article that shows and explains the various connector types.

expert reply by: Michael H

0

Dennis L.

5/8/2020

Can I get a plug and play trailer wiring kit that requires no cutting of wires to go with hitch from you for 2001 freightliner MT45 former snap on truck going to be used as off grid rv?

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Chris R.

5/12/2020

There isn't a custom plug-and-play harness available for your 2001 Freightliner MT45 (I really wish there was!). You'll need to go with a hardwire kit like the excellent Tekonsha # 119147KIT for the 4-Way connector. If you need a fully functional 7-Way, you'll then use the Wiring Kit # ETBC7, which includes everything needed to convert the 4-Way to a 7-Way connector.

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Danielle D.

5/13/2020

So I have a camper with a 7 round and a vehicle with a 4 flat pin. Can I just buy an adapter or will I not be able to use the brakes on the camper, only the lights?

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Chris R.

5/16/2020

If you were to just hook up an adapter like the Tow Ready # 30717 (without running those additional wires) you would only be able to activate/power the signal lights on your trailer. If the trailer has electric brakes a better option is the Wiring Kit # ETBC7, which includes all the additional wiring needed to activate the rest of the circuits. You'll also need to add a brake controller like the Prodigy P2 # 90885 to your tow vehicle (if you haven't already).

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William W.

5/26/2020

Is there an adapter available to go from a 7 pin wire connector on a 2014 ford truck F350 to a trailer plug which is a 9 pin? And if not whats different from a 7 way versus a 9 way? Thank You,

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Chris R.

5/29/2020

There isn't a clean adapter available that goes from a 7-Way to a 9-pin connector, but we do have still have solution. I've linked an informative answer page below that details the parts you will need.

Helpful Links

etrailer.com/question-126746.html

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Joel M.

5/28/2020

Have Titan xd 2016 pro 4x has factory 7 way and 4prong wold like to get 7 way on a old car hauling trailer. Backup lights, brakes. Do you have plug ready for trailer, need to re wire and light whole trailer, and brain transplant for myself. Can you help me please? Thanks

Reply

Chris R.

5/29/2020

Unfortunately I can't help with the brain transplant (I'm on a waiting list myself) but I can with everything else! To wire your trailer up with a 7-Way connector, I highly recommend using the etrailer 7-Way Upgrade Kit # e99011. This allows you to make this conversion and keep all your connections clean. For extra wiring you can use 12 gauge # 12-1-1 for the brakes and 12V circuit and 16 gauge # 16-4B-1 for the lights, both of which are sold by the foot. It sounds like you're also wanting to add or replace some light assemblies as well - I've linked our full selection below if that's the case. I also linked a handy wiring article that you might find helpful.

Helpful Links

dept-pg-trailer_lights-sf-tail_lights.aspx

faq-wiring.aspx

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Boris G.

7/29/2020

for a ford transit 250 which is what I need to install to connect a trailer with 2 axles with brakes, and where I could make an appointment to do the work with you. Thank you

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Chris R.

8/3/2020

I can definitely get you set up with the correct parts to add to your Transit 250. Just to be sure I recommend the right components, can you tell me what model year the vehicle is?

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Boris G.

8/4/2020

It is a ford transit 250 of the 2018 Medium, remember that if you can give me any address where I could get your services. Thank you

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Chris R.

8/13/2020

Thanks for the info! Starting with the hitch, the Curt Class IV # C14012 will work really well. Then for wiring I recommend the Tekonsha # 22114, which includes everything needed to install a fully-functional 7-Way connector. The kit also includes wiring to install a brake controller (which is needed for your trailer) like the excellent Tekonsha Prodigy P2 # 90885. We are located in Wentzville, MO so if you're nearby we can definitely set up an install - just give our Customer Service team a call at 800-298-8924 and they can help you out with this.

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Darin F.

8/10/2020

I just bought a 2019 Ford Ranger Lariate w/ tow package in March. Ive towed my camper twice; it seems the trickle charger from the 7 pin is not working (so the mini fridge in the camper wont run to keep things cool while traveling.) If the tow package missing this feature, or is there something I have to turn on?

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Chris R.

8/13/2020

The 2019 Ford Ranger should have that 12V circuit activated as part of the tow package, but it's a little odd in how you actually get it to send power. I linked a separate answer page below that does a nice job of explaining this.

Helpful Links

question-420310.html

Reply

Audrey

10/23/2020

@DarinF — Unless you have a residential fridge with an inverter your tow vehicle will have virtually no affect on whether your fridge will run. Your fridge can run in one of two conditions: 12V AND propane, OR shore power. If you have only 12V power available (such as when towing), your fridge needs propane to stay cold; the 12V runs the circuitry, burning propane cools the unit, and the TV charge on the battery should be able to keep up with that demand. The cooling process of the fridge does not run directly on 12V. Even if your battery is not being charged by your tow vehicle, assuming a healthy battery, your fridge should run on propane for long enough for a day on the road with just the charge on the battery. But there are A LOT of factors that work into that. The decision whether to run the fridge on propane while traveling has been widely covered here and elsewhere, so that decision is up to you. Personally, I run mine on propane in transit and always have. My fridge runs "end to end", meaning I keep it plugged into shore power at the house, run it on propane (or generator) in transit, and shore power/generator while camping. Same for the ride home. I don't turn it off until I have all the food out at the conclusion of a journey. If you don’t want to run the propane while in transit your food should still stay cold. Just make sure your fridge has had long enough to become cold and the food you added is cold as well. If you still can’t travel at least 8 hours without your food getting warm then you have something wrong with the fridge like maybe the seal leaking. Also keep in mind that some very new campers are made to automatically switch off the LP when the camper senses motion.

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Steve R.

4/21/2022

@DarinF the fridge isn't meant to run off the battery. I use shore power the day before a trip to cool the fridge, then plug it back up when at the camp site. They run on 110 ac and your battery is 12 v dc

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Jim K.

9/8/2020

My 2019 Minnie Winne has a 7 pin connector in rear for flat towing. What wiring harness/connector do I need for my 2018 Wrangler Unlimited? I want to get the patriot II, can I keep it plugged in recharging while driving, through the RV connections or do I need to install a 12v hot wire for the Patriot II?

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Jon G.

9/11/2020

Here are some shopper's guides we put together for Jeep owner's that breaks down everything that you need whether you have the JK or the JL.

Helpful Links

faq-flat-tow-package-jeep-wrangler-jl.aspx

faq-flat-tow-package-jeep-wrangler.aspx

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Moriarty

10/28/2021

Totally new to this, so go easy ;) Doing a ground-up rebuild of a 4'x8' single axle utility trailer that will have a basic lighting setup, but I would also like to install a powered winch (i.e. Badlands 2500 from Harbor Freight). I would like to wire the winch into the lighting harness (or get a harness that includes the necessary wiring) so that when the trailer is plugged in to my truck (has 4-pin and 7-pin connections) everything will work. What's the best way to go about this? Is there a 7-pin harness I can install and just hook up all the lights and the winch to? That would be ideal. If not, I have a 4 pin harness already; how can I tie the winch in to that?

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Les D.

10/29/2021

@Moriarty I would install the etrailer # e99011 7-way cord and junction box. This will give you a secure place to make all of your connections, and give you a standard 7-way connector that many vehicles can connect to . If you use a 5-way or 6-way connector to run from truck to trailer you will not find many trucks that could connect to that.

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Tim H.

3/25/2024

Hello, If I use a 7way cable connector to my towed car. Can I use the 7way to connect to my car and charge my car battery?

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Jenny N.

4/17/2024

@TimH Yes you can use the 7 way [or 6 way] to maintain the vehicle's battery charge as long as the motorhome has a charge line run to the battery. You would want to check the 7 way to make sure that the 12V hot lead is active by using a circuit tester like part # PTW2979. If not you can use part # RM-156-75 to run a charge line from the RV battery to the RV 6 or 7 way. You would also need to make sure you have a 6 or 7 way on the front of the towed vehicle. And use part # RM-156-25 to connect to the vehicle's battery.

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Leonard

7/17/2024

Can I purchase a kit to wire a 7 pin setup with a brake controller to be installed in my 2008 honda element?

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Andrew N.

7/17/2024

@Leonard Yes, you absolutely can. You'll first need a 4 way flat trailer wiring harness, which you may already have, but if you don't, you can use Curt T-Connector Vehicle Wiring Harness with 4-Pole # C56029. Then you can convert any 4 way flat to a 7 way to work with a brake controller by using our # ETBC7 kit. If you then need a brake controller (assuming you don't have one yet), you can wire in something popular like the Tekonsha Primus IQ # TK90160.

Helpful Links

tv-install-universal-brake-controller-install-kit-2019-toyota-highlander-etbc7.aspx

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Gary D.

8/10/2024

My dealer has messed up getting an electric brake controller onto my '05 Toyota Sequoia Said the unit was bad out of the box never even checked the troubleshooting guide because he had quote unquote installed lots of aftermarkets on the vehicles. The accessory Tech as he was called was in his twenties by the way. Can you tell me the setup I need for a proper hookup because I need to pull a 4000 lb trailer and need my electric brakes to be functioning

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Bryce D.

8/12/2024

@GaryD Hey Gary, well unfortunately for you I am also in my twenties, but I'll go ahead and get you going with a list of parts needed to add a brake controller to your 2005 Toyota Sequoia. The first thing you're going to need if you don't have one already is a 4 pole # 119147KIT. From here, the next part you're going to need is a 7-way, with # ETBC7. Lastly, you'd just need to add a brake controller. It sounds like you already have one, but if you don't the Tekonsha Prodigy P3 # 90195 is an excellent choice, and will work great with your Sequoia pulling a 4,000 lb trailer. If you have any other questions, feel free to come back and we'd be happy to take care of you.

Reply

Gary D.

8/12/2024

@BryceD Wow wish I had had such an excellent response time from my dealership as I did on the subject from you. I do already have a factory tow hitch on my Sequoia and the technician at the dealership purchased and installed would appears to be a custom type pigtail already wired in behind the driver side left panel. If I was at home I could send you the numbers that are off of it. I gave you in and did however put in a one star review to the dealership this past Saturday detailing all the inadequacies of the accessory technician who dealt with my truck there was more than just that one issue so I'm waiting to see what their reply may be I have however written down the parts numbers that you sent here and will be checking them out. Again thank you so much for such a fast response hopefully the wife and I will be able to do our vacation as we planned because at this point either insurance wise or legal requirement wise I can't put that trailer on the street at all just now.

Reply

Bryce D.

8/12/2024

@GaryD I hope for the best, Gary. Feel free to come back anytime.

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Andrew M.

4/13/2025

hello Michael or ?, Just purchased a brand new 2025 Hyundai Palisade Calligraphy SUV with an incredible amount of computer technology. I have a 5x8 carry-on trailer with 4 way flat plug. Need an adapter to accomodate my Hyundai SUV which has LED Lights and many many other electrical features. Please reccomend the proper adapter to fit my 7 Blade factory tow connection. I would appreciate your professional and experienced opinion a great deal. Thank you very much, Andrew matteson

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Robin H.

4/13/2025

@AndrewM for a 7-way to 4-way adapter I recommend the Curt # C35FR. This has built-in resistors so your computer technology doesn't think a light is out or the trailer is disconnected if you tow a trailer with LED lights. Even if your current trailer has incandescent lights this would be good to have just in case you tow a different trailer later on. It is compatible with both.

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