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

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

Item # 37185
Retail:$65.39
Our Price: $59.28
You Save: 9%
Trailer Wiring
Shipping Weight: 0.94 lbs
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Hopkins Wiring Adapters - 37185
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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. Great Prices for the best trailer wiring from Hopkins. Adapter 4-Pole to 7-Pole and 4-Pole part number 37185 can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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  • Reviews (608)
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Hopkins Trailer Wiring - 37185

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




California residents: click here


Customer Satisfaction Score:


Customer Reviews

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

Average Customer Rating:  4.8 out of 5 stars   (608 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.

by:

Really nice trailer wiring adapter. Very easy install. Takes about 30 minutes with all the tools needed. Drill, 7/64 bit for pilot holes to mount the bracket, flat blade screwdriver and 11/32 nut driver and two #10 self tapping metal screws with locking split washers and a couple zip ties to tidy up the wiring harness.



by:

Installed on our 2019 Edge ST with no significant issues. Works as expected, has reasonable required depth behind connector for ease of install, and the bracket was quite adaptable after some bending and cutting. Not impressed with the overall feel, though - plastic seems lightweight and cover hinge pin is already rusting after two winter weeks in western PA. Long term durability tbd.



by:

Easy installation, does exactly what it is intended to do.



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.



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!



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.



by:

Worked great in tandem with a new wiring harness. Still working after a year of use.



by:

This company is amazing as they offer an incredible vast inventory of most anything one can imagine relating to trailers. They sent a nice email confirming the order and notice of being shipped, which arrived in just three days.



by:

I recently installed the 4-pole to 7-pole adapter on my 2015 Highlander. My first install worked OK, but I ran into a ground clearance issue using the original mounting location. Etrailer suggested using a 2 1/2" mounting box to relocated the connector. Part number 18156 worked perfectly.



by:

The trailer wiring adapter was perfect and shipped in no time. Looks great on my ford ranger. Im very happy.
Was 4 flat only and now I can light my 7 way 18' trailer and have the capacity to add a brake controller (which I will add)



by:

Just like always from etrailer, the right product, right on time, and right on the money.



by:

Very helpful nice and good price great quality



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.



by:

I bought this so I can convert my dad's trailer to pull I only had a four and I needed a seven so I went and used a four to make it a seven. It's a very nice product it's got nice rubber grommets to keep everything protected.



by:

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



by:

2012 Chevrolet Express..Looks and works great! Easy install..2 1/8" hole saw for center, 3/16" drill bit for mounting screws. Thank you etrailer!



by:

I use these adapters to install 7-way connectors on trucks that have no factory trailer wiring provisions.



by:

Used on my wifes van and works great with our camper. Only complaint is wish is had a way to stabelize to the vehicle a bit better two screws at the top are all that hold it on to the van.

Etrailer Expert

Jenny N.

3/2/2023

I recommend using part # 18140 which will zip tie to the hitch. Then you can attach the harness bracket to the end of this bracket.



by:

Wow after Charles great advice this was so simple to install, [online] 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!



by:

Great product and description. Installation was very easy and smooth. Everything lined up, the installation video was on point



by:

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



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.



by:

I had a great experience. Got the product with no problems.



by:

Thank you so much! You all are so attentive and helpful!



by:

Great service. My questions were promptly answered as which wiring kit would fit my 2004 grand Cherokee without having to fabricate wire connectors and such. They gave me several options and explained the differences between them. It made my decision easier . I received my kit sooner than i expected. I haven't installed them yet, because I still have to put the hitch on, but I am sure it will be basically a plug and play deal. I would recommend etrailer to everyone just in the service alone. Thanks guys.

Peter

9/13/2019

Works excellent. Easy install and no problems doing it.


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See what our Experts say about this Hopkins Trailer Wiring

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    It sounds like you are just needing the Hopkins Adapter 4-Pole to 7-Pole and 4-Pole # 37185. This will plug right into the 4-Way flat on your tow vehicle and provide a 7-Way to connect with your trailer. Since you are only needing to power the lights on the trailer, the additional wires can simply be tied off as they will not be needed. I have attached a short video demonstration on this product that you can also check out.
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  • 7-Way Recommendation for a 1999 Ford Expedition
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  • What Circuit to Use for Running Light Activation of Observation System Camera
    The running lights circuit would be the correct circuit to use for the camera setup you mentioned. I am not sure why it's only showing 6 volts but it should be a 12 volt circuit. This can also still be used for the running lights of your trailer as well. Normally the center pin of the 7-way is the aux/backup light circuit but this circuit isn't always active so you may have to verify that with your tow vehicle. This would be the number one pin of your picture.
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    I have included a diagram that shows the two ways in which 2 batteries can be wired together. Having two 6 volt batteries wired in parallel will produce 6 volts still but increases the capacity. The other way is to wire two 6 volt batteries in series which would double the output to 12 volts but the capacity remains the same. In either case the output side would go to the power wire on the trailer to power trailer mounted accessories.
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    The fact that your trailer lights seem to work just fine until the vehicle headlights are switched on indicates a ground problem somewhere in the system. The quick way to confirm a ground problem would be to disconnect your existing ground connection from the trailer and use a butt connector to temporarily connect a length of wire long enough to reach the negative battery terminal. If this temporary jumper fixes the problem (which it most likely will), you have confirmed a poor ground...
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  • Switching Trailer from 7-Way to 4-Way and Right Turn Signal Does Not Work
    On a 7-Way blade style trailer connector the brake lights and turn signals are on the same circuits. So you will have one for left turn and brake lights and another for right turn and brake lights. If the brake lights are working on the right side then the turn signal should also be working. If it isn't then there is likely 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...
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  • Bolt Doesn't Want to Thread to Install 7-Way Bracket On a 2011 Nissan Pathfinder
    It sounds like the existing weldnut on your factory hitch has gotten corroded over time and that is why the 8 mm bolt will not thread into it. This is a very common problem on vehicles that have seen a couple winters or more. I attached the video you referenced and at the 1:47 mark of it our installer shows how to install the bracket. I also attached a couple articles on cleaning weldnuts for you to check out as well.
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    For your 2005 Ford F-150 there is the brake controller wiring already present on the frame rail of the truck. Follow the 4-way trailer connector wires from the trailer connector to the front of the vehicle. These wires connect to a factory plug along the frame rail, usually on the driver's side, between the back tires and the rear bumper (Figure 2). The factory plug should be mated to another connector which has wiring that continues back toward the bumper. There are more wires coming...
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  • 4-Way to 7-Way Adapter Recommendation
    The most popular 7-way to 4-way adapter we have is the part # 37185. This plugs into your 4-way and gives you a 7-way. You can also run the other wires on your vehicle if the additional circuits are needed. Plus there's a 4-way on the side of it which allows you to not need to remove the adapter when a 4-way is needed.
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  • Diagram for Wiring 6 Volt Batteries in Series and in Parallel
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  • Troubleshooting Trailer Jack that is Moving Slowly
    A powered trailer jack operating slowly can be from bad wiring (insufficient ground or weak connections), a weak battery that's not able to keep up, or the motor of the jack is bad and would need to be replaced. I would first try charging your trailer battery and checking to make sure all of the wiring is solidly connected.
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  • How to Wire Two 6-Volt Batteries In Series to Produce 12-Volts of Output
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