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Adapter 4-Pole to 7-Pole and 4-Pole

Adapter 4-Pole to 7-Pole and 4-Pole

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Wiring 37185 - 7 Blade,4 Flat - Hopkins
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Adapter converts from 4 pole wiring on vehicle to 7-pole round plug and 4-pole flat. Additional wire leads for brake, power and accessory. Lowest Prices for the best wiring from Hopkins. Adapter 4-Pole to 7-Pole and 4-Pole part number 37185 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
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Hopkins Wiring

  • Wiring Adapters
  • Multi-Function Adapter
  • 7 Blade
  • 4 Flat
  • 4 Flat
  • Plug and Lead
  • Hopkins

Adapter converts from 4 pole wiring on vehicle to 7-pole round plug and 4-pole flat. Additional wire leads for brake, power and accessory.


Features:

  • Adapter converts from 4-pole wiring on your vehicle to 7-pole round plug and 4-pole flat wiring for trailer side
  • Adds additional wire leads for brakes, power, and accessory wiring
  • Wire functions:
    • White - ground
    • Blue - brake
    • Black - hot lead - 12 volt power supply
    • Purple - auxiliary
  • Mounting bracket included


Specs:

  • Connector measures 3" x 3"
  • Distance between vehicle mounting holes: 2-3/16"
  • 90-Day limited warranty


product detail

Wire Functions:
White: Ground
Blue: Brake
Black: "Hot" Lead - 12V power supply
Purple: Aux. - Reverse Lights etc.





Note: If you run the hot lead (black wire), you will need a circuit breaker, for example 9510 (sold separately), between the adapter and the battery itself.



47185B Adapter 4-Pole to 7-Pole and 4-Pole - Hopkins # 47185B, TAP # 37185

Item # 37185




California residents: click here


Video of Adapter 4-Pole to 7-Pole and 4-Pole

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




Video Transcript for Trailer Wiring Harness Adapter Installation - 2010 Ford Explorer

Today on our 2010 Ford Explorer, we're going to take a look at and also show you how to install the Hopkins Wiring Adapter for converting a four pole flat into a working seven pole and four pole. Part number is 37185. Here's what our wiring kit is going to look like when we pole it out of the package. This is a really excellent way to adapt the plug on the back of your vehicle from being just a single type, either the seven pole or four pole than having to use adapters. As you can see we've got our four pole here. It's going to fit your common four pole flat trailer connector with ground, running lights, left turn and brake signal and right turn and brake signal. For our seven pole side, this is going to give us the additional functions of twelve volt power if we hook it up, our brake controller wire if we hook it up and also a reverse signal if we hook that up.

Also of course it's going to have the standard light fittings. You'll see inside we've got our gasket all the way around that door. It's going to come down and seal that up. It's going to prevent the dust and the moisture from getting inside and the same with our four pole there. It's got a nice cap to keep everything protected. Now the wires coming out of the back, we're going to have our four pole plug here, we can plug this directly into an existing four pole plug.

That's going to make that very easy. Then we'll have our purple wire, that's typically what you're going to use for reverse light signal. Got a blue wire here which is what we would use for a brake controller signal and then we've got our black wire here. This is what we would us for our twelve volt power. Now our customer has requested just the reverse signal hooked up so that's the only one we're going to be doing.

If you hook up twelve volt power to your battery, be sure to use one of the breakers that we have available on our website and for a great controller wire, you would essentially just have to run this from here along the frame of your vehicle and inside to your brake controller. That's going to be a direct connection. Also the white wire that already has a ring terminal on it, we're going to be grounding that out to the frame of our vehicle. We'll be using a number twelve self tapping screw. You would have to provide that for yourself. We've also got a bracket that's going to slide right onto the backside of our plug there and we're also going to have the hardware we'll need to install that.

It's usually with that four pole cover removed. We've got four locations there. Then we've got our lock nuts with serrated washers on them that will go on the back. Now to secure that you'll just need a flat head screwdriver and then you can just hold the nut as you tighten it down. For the blue and black wires, since we're not going to be using them, we're going to eliminate some of the length here. Just like that. We want to leave them in case the customer ever changes their mind that they want to add on to that, that will be fine and then just from the back side here, I'm going to run tape down. About here just so we have a nice clean appearance there on the back side of our vehicle. Now if you have the already existing four pole on the back of your Explorer, this is going to plug right in. If you don't you'll have to go with one of the kits on our website. Now we still got good length on our wire and just so we don't waste this ring terminal, we'll just run this right up over our frame rail. It's going to take up some of that slack and we're going to mount it right here to this steel panel on the back. We'll use our number twelve self-tapper here and get our hole started. Bring our ring terminal down and secure it up. Now if you are trying to wire up a reverse signal which would be typically for a marine trailer application with surge brakes, as you back that trailer up, this is going to over ride the brakes so they don't lock up on you. If you don't need your reverse light signal, then you'll just want to skip over this section because it's not going to be that important to you. But to find it we're going to remove the tail light housing here. We're going to take out the two bolts here and here. Eight millimeter. Gently pull out on the housing there. It'll clip out of its couple little pressure fit fasteners there. Just like that. Now we now our reverse light is in this section, that's the clear section. What we need to determine is which one of these have the power signal. One of them is going to provide power, one of them will provide ground so let's place the vehicle in reverse and we can test that. Just use a twelve volt power tester, test each of the wires and see which one we get our signal from. All right, looks like it's going to be the lighter colored brown wire in our application. We'll just remove a little bit of this loom so we can get a splice put in there. Now we've got a small piece of twelve gauge wire here. We're going to run this right down in between the body of the vehicle there and the bumper cover. You'll be able to pull that down and through so we can make our connection on that lower side and then we can splice into that. When we're inside it doesn't matter which one but you want to splice that off about twice as long as what you typically would, twist it and then just fold it over. That's going to give us enough wire for our butt connector to bite on to. Give us a good secure connection. We'll strip off that other side just to normal length. I've already got my twelve gauge wire stripped here. Give this a little bit of twist together and we'll go right on the other side of our butt connector. Now we can just use a heat gun, you can use a mini torch or in this case we're just using a lighter. We're going to heat up the end of our connector here. You'll see it start to shrink down. Now we can just get that housing popped back into position and replace our two screws here and you'll be ready to hook up the rest of our wires down below. Use a couple of zip ties here and kind of tidy up our wires. These two are going to split off this way so that's why I'm going to separate them here. Do the same thing up here where those two come over the frame rail. There's another piece of wire look there we can connect them to. Now we're going to use a little bit more tape and just get all this wrapped up and it will be nice looking underneath the vehicle and not like a bunch of multicolored wires. Now we'll bring our bolts down through the bracket on our hitch. Now if your hitch doesn't have a bracket that's attached to it, you can pick up part number 18140, it's going to be our universal short mounting bracket. Should do the trick for you just fine. Slide that on and then place on our washer and our serrated lock washer there and then just thread on our nut. All right, that's nice and secure. Now we'll just tidy up our little bit of excess wire we've got here, just zip tie that right around the hitch and we won't have to worry about it. All right, now we'll test out our four pole side first. We'll connect our ground clamp to the ground stud. The running lights are on, check for that. All right. Now left blinker. Now right blinker. And brakes. All right, all of our signals are working fine now. Let's switch over to our seven pole here. And running lights off. And back on. Okay good. Now brake signal. You see for our brake signal we're getting good solid signal on both of those. Now our left turn. Now our right turn. And our backup signal. And reverse off and back on. And off. And of course we won't have brake controller or twelve volt power signal because that wasn't requested. Now with everything working properly that's going to conclude our installation of the Hopkins wiring adapter for converting a four pole to a working seven pole and four pole. Part number 37185 on our 2010 Ford Explorer.


Customer Reviews

Adapter 4-Pole to 7-Pole and 4-Pole - 37185

Average Customer Rating:  4.8 out of 5 stars   (392 Customer Reviews)

Adapter converts from 4 pole wiring on vehicle to 7-pole round plug and 4-pole flat. Additional wire leads for brake, power and accessory.

- 37185
by:

Like the products, easy to install. 611154



- 37185
by:

I have used this trailer hitch and its wiring package without a problem. the last time I pulled a trailer it was heavy enough to slow me down to 35mph when I was going up an on ramp. my last trip was over 300 miles and had no problems 578241



- 37185
by:

I use this matching unit to replace the broken cover(plug lock) parts & spring on my hard wired connection. It's a good product unless/until the plastic hinge breaks(especially if one backs into something). It's less costly to strip/swap parts than a new plug + rewiring. Just wish they made a metal version, or could get select "parts". 81184



- 37185
by:

Another great product as always. Exactly what i needed. Thank you etrailer 600088



- 37185
by:

Installed and connected. Used the existing grommets and cut a slit and small hole in the middle to go up through to the inside. If you take the inside grommet out on the back side Above the bumper after removing the carpet you can feed the cable down through both holes and reinstall the grommets. Mounted the ground wire on the drivers side to the metal frame on the drivers side using existing holes for the grounding wires. Used a hole drill bit to drill a hole just large enough to slide the connector in and bolted directly to the bumper not using the L bracket. Connector is flush with the bumper and used the 4 bolts provided. Took overall three hours to do it all. 643474



- 37185
by:

After taking my new SUV to the dealer to have it wired to tow my camp trailer, I was told it couldn't be done. They refused to see that the vehicle had the tow package and to help me get the last few critical pieces to tow. I guess they were too busy! So I tried a reputable RV shop that I have worked with before and they quoted me over $400 to custom wire my SUV. I knew there had to be a better option. Looked online and found etrailer. They made it sound easy. I purchased: Tekonsha PowerTrac Electronic Brake Controller (39523), Tekonsha wiring adapter (3035P) and 4 pole to 4 & 7 pole adapter (37185). It all arrived quickly and after following the instructions online and even with average mechanical skills, I was good to go in about one hour. Saved about $300 and whipped it out that fast. Why consider any other option. I am extremely satisfied. 59917



- 37185
by:

This was exactly what I was looking for to add to my 2017 Ford Expedition! It is an easy to install plug-n-play product to convert a factory 4-pin connector to a 4/7-pin connector. I plugged the 4-pin in, connected the brake wire, and grounded it. Ignoring the auxiliary + power cables, everything worked on the first test. The 4-pin connection was given some dielectric and wrapped with electrical tape to keep it sealed from the elements, and the slack was zip tied to secure it. I still need to give it some finishing touches (fill the bracket gap with some black silicone, maybe find the reverse and/or power lines), but it lets me haul my camper! 635819



- 37185
by:

Great product fast shipping.. used on 2004 Lincoln navigator. 479026



- 37185
by:

Product was shipped and arrived sooner than expected. Mounting plate is a little thin and flexes quite a bit but shouldn't impact longevity as long as your careful when inserting plug. Unit is made of high impact plastic and wires are sealed. Don't see any reason why it shouldn't last a few years. 4 way plug didn't fit into my stock 4 way on my truck. I had to remove excess rubber in order to make it fit tight. Not a big issue but one should expect some standardization among 4 way plugs. Ground wire (white) is separate from the 4 way plug. Not sure as to why it was built that way but still functioned well. Regardless of my concerns, item was installed and up and running in about 20 minutes. I would buy again. 133653



- 37185
by:

Wow after Charles great advice this was so simple to install, YouTube video was point on and the hardest thing was finding the reverse wire. Thanks so much for a good product and excellent advice, here is the pic after install! 500490



- 37185
by:

If you have 4-flat and need RV, this is the connector for you. Easy to hook up (unless you need to wire in the brake controller). I needed to convert my Corolla 4-flat to 7-pin RV to match my VW Vanagon and motorcycle trailer with newly installed brakes. I haven't hooked up the brake controller yet on the Corolla but I needed the plug compatibility 'til I do. 217850



- 37185
by:

Installed on a 2010 Ridgeline. Just what I needed at a great price. Install was a breeze. etrailer is the best place to find all the stuff that auto dealers rip you for. Good quality and the customer service is above reproach. 501788



- 37185
by:

I installed the ETBC7 kit a year ago, and a recent trip wiped the plug off while crossing a stream. This was a perfect replacement for my damaged plug and easy to install. 94452


Comments
It is working fine. No problems.
Ron J - 08/13/2014

6242

- 37185
by:

instructions as well as posted video made installation very easy and the parts themselves are well constructed 647812



- 37185
by:

Just what I need to tow an RV trailer. Also has a four flat connector. Very easy to install on the 18136 bracket. 63719



- 37185
by:

Provides a 4 pin and 7 pin connector in one compact package. Rear housing is considerably shorter than most, so it's less likely to interfere with the hitch cross member. Includes a mounting bracket, or works great with Curt C58000 bracket. Only complaint is that the 12V wire is quite short, so a crimp connection needs to made very near the connector. Be sure to seal that connection against corrsion. 458708



- 37185
by:

I installed this along with a brake controller on my 1997 Nissan Pathfinder earlier this year and it was easy to install and the instructions were nicely detailed. I do have some mechanical skills so I would say you need to have some knowledge of electronics, but if you do some careful planning and study, most people could handle the installation. I toasted my plug on some rocks on my last outing so I purchased this to replace my original one. It's a great product. As always, etrailer is very helpful and their knowledgeable staff make it a pleasure to do business with. 259017



- 37185
by:

Works as advertised 567566



- 37185
by:

Nice quality adapter harness. I would highly recommend etrailer.com 134651



- 37185
by:

This kit is fine for what it is. It is not designed for those who have no existing wiring in the vehicle. You will need ETBC7 if you want an all included kit that provides added wires and fuses for customers who don’t have trailer break or reverse light wiring already installed. If you don’t need the extra material, this is a great kit to turn a 4 pin into a basic 7 pin connector. Also, be aware, you need to look and see where you want to mount the connector. You may need an addition adaptor plate to mount the bracket to the trailer hitch if you don’t have a good location available. 541243



- 37185
by:

2018 wrangler unlimited Sport S. Without trailer wiring. Completed installation today. Used a 4 flat along with a 7 pin converter. Works and fit perfectly. Very hot day and work slowly and carefully. Very satisfied . Great folks at etrailer. Great products, great quality and prices. I'm a several time repeat customer and couldn't be more satisfied. 4 pin harness Was a 56407 and the 7 pin adapter was a 37185. 539606



- 37185
by:

This item was received without instructions. The 4pin is easy enough to plug into any other 4 pin. Once you ground the white lead the brakes and signals work well. I dont know what the blue or purple wires are for, as instructions did not come with this item- wiring diagram either. Black lead I assume is power, to be connected to a hot lead, for internal trailer lights, idk. Otherwise, I am happy. 527702


Comments
The black wire is the power wire it needs to be connected to the positive side of the battery by using a 40 amp circuit breaker. If you are using your reverse trailer lights attach the purple wire coming out of the 7-way connector to the your reverse light wire. The blue wire is for electric brakes its going to go to the output wire on your brake controller. There should be a black wire coming from your brake controller that will connect to the positive side of the battery as well using a 20 or 30 amp circuit breaker. The red wire from the brake controller will connect to the cold side of the brake switch above the brake pedal. The white wire on the brake controller grounds to the negative side of the battery. I have attached help articles to assist you.
-- Heather A - 07/10/2018

40767

- 37185
by:

The product itself is very well made. The 4-pin connector is molded into the product and very sturdy. The 7-pin connector is held closed by a spring and has a foam gasket to keep water out. The 4-pin wiring is only about a foot long, and the additional 7-pin wiring is a bit longer. I do not have a brake controller (but do borrow a trailer with the 7-pin wiring), so I removed those wires. I also hard-wired all the connections, so I can't speak to the quality of the 4-pin vehicle connector. The mounting bracket is thin steel, which worked well for me, as I had to bend the mounting plate to make it work for my installation. The paint on the mounting plate appears to be high quality as I bent the plate and banged it around quite a bit during install and did not nick the paint. The plate is drilled so that is can be mounted with the 7-pin hinge facing up, down, left or right. The hardware is zinc coated, so it should hold up well to the weather. I went ahead and replaced it with SS to make sure. I also replaced the standard nuts with SS nylon lock nuts to make sure nothing would back out due to vibration. If you plan on using the supplied hardware, I would strongly suggest Loctite on the mounting nuts. I installed this on a CX-5 with hitch # 87623, wiring adapter # C56011 and hitch cover # I-728. Over all a very clean installation. The connector is completely hidden inside the bumper, but easily accessible. 72768



- 37185
by:

Hitch arrived in a timely fashion. Installation was a breeze and the fit and finish were perfect. Wiring harness hooked up perfectly. etrailer made the whole process simple. I just ordered another hitch and harness for our new car. 379041



- 37185
by:

I haven't installed chains or boat trailer plug and 7 way cord yet.I would like to say that etrailer's quick shipping is second to none!!I buy a lot of things on line like ebay,but I am really impressed by your U.S map tracking system.Before I bought my items I emailed you to make sure of the fit,Your response was fast. 326755


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  • Parts Needed to Add a 7-Way Trailer Connector to a 2011 Toyota FJ Cruiser
    What you will need is the 4 and 7 Way Installation Kit, # ETBC7. This kit comes with everything you will need to add a 7-Way and 4-Way trailer connector to your 2011 Toyota FJ Cruiser. It also provides some parts for a brake controller. If you have a trailer that requires a 7-Way connector, it probably has electric brakes and you may want to consider a brake controller. I have included a link to an FAQ article and a link to a video that explains the installation of an ETBC7 kit. You...
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  • Does Hopkins 4-Pole to 7-Pole Adapter Work on 2017 Hyundai Santa Fe?
    The Hopkins Adapter 4-Pole to 7-Pole and 4-Pole # 37185 will work with a 4 flat on your 2017 Hyundai Santa Fe, though it won't give you the functions of the 7-way. If you are looking to install a brake controller you will also need the Universal Installation Kit for Trailer Brake Controller # ETBC7 to complete your wiring. This kit actually comes with the # 37185 adapter so you would not need to purchase it separately.
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  • Installation Of 4-Pole to 7-Pole On 2006 Ford Expedition
    I recommend using the Hopkins Adapter 4-Pole to 7-Pole and 4-Pole, part # 37185 for your 2006 Ford Expedition. I have attached a photo of the adapter that shows the wires and what they are used for you can check out. You can find the wires you need to connect the adapter to on the driver's side frame rail as shown in the photos I have attached. I have also attached a helpful article that explains how to complete the installation. I recommend using a circuit tester like part # 3808 to...
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  • Parts Needed to Install 7-Way on 2011 Nissan Pathfinder
    If your trailer does not have brakes your best and easiest route would be to use the adapter part # 37185. Your 4-way plugs into it's 4-way and you have both a 4-way and 7-way with just taillight functions. If you need trailer brakes you'll need quite a few more things. To star you'd need the part # 118281 for a 7-way. But you'd need to swap out the socket to the part # HM40975 as it will install and give you both the 4 and 7-way. For a brake controller I would recommend the Prodigy...
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  • Adding a 7-Way Trailer Connector to a 2016 Honda Pilot
    If the 7-Way trailer connector on your 2016 Honda Pilot is the factory installed 7-Way then all of the functions, including the 12 volt power circuit, should be active. But on models that did not come with the factory harness the connection and wiring is there but may not be active. However, you will not have to hardwire in a 7-Way to your Pilot because you can use # 118286. It plugs into the factory connection point and includes the fuses and relays to make it active. I have linked...
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  • Wiring Harness for Flat Towing 2004 Jeep Wrangler
    We can help you get set for flat towing your 2004 Jeep Wrangler with your motorhome but we do not offer any wiring adapters for an 8-prong motorhome socket. Most motorhomes these days use a 7-way blade style connector like the one shown in the linked photo. You can convert the MH to a 7-way using a part like # 37185 or # PK12-707E. You'll just need to match up the functions; a circuit tester like # 40376 makes this easier. We do have a plug-in flat towing harness for your 2004 Wrangler,...
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