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Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket - Metal - Vehicle End

Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket - Metal - Vehicle End

Item # PK11404
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Establish a secure connection between your trailer and your towing vehicle with this 4-pole, round pin, wire-insertion style socket. Zinc die-cast socket has concealed terminals to provide easy assembly and durability . Lowest Prices for the best trailer wiring from Pollak. Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket - Metal - Vehicle End part number PK11404 can be ordered online at or call 1-636-306-4830 for expert service.
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  • Reviews (94)
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Pollak Trailer Wiring - PK11404

  • Trailer Connectors
  • Vehicle End Connector
  • 4 Round
  • Plug Only
  • Pollak

Establish a secure connection between your trailer and your towing vehicle with this 4-pole, round pin, wire-insertion style socket. Zinc die-cast socket has concealed terminals to provide easy assembly and durability .


  • Heavy-duty, metal, 4-pole socket connects trailer to towing vehicle
  • Round brass pins
    • Minimum voltage drop is ensured
    • Dielectric (non-conducting) grease coating
      • Protects against corrosion and resistance
    • Wire gauges up to #12 gauge wire accepted
  • Concealed terminals for durability
    • Provide easy assembly
  • Spring-loaded lid
    • Keeps dust and moisture out of interior
  • 2-Hole mounting style


  • Fits Pollak Heavy-Duty, 4-Pole Round Pin Connector (PK11402)
  • Does not fit Pollak Heavy-Duty, 4-Pole, Round Pin (PK11409)
  • Mounting dimensions: 1-3/8" diameter hole
  • Mounting screw holes: 1/4"
  • Volt rating: 12 volts - 24 volts
  • Current rating: 35 amps
  • Wiring configuration:
    • Color - circuit:
      • White - Ground Return
      • Green - Right Turn and Brake Lights
      • Yellow/Red - Left Turn and Brake Lights
      • Brown - Tail Lights
  • 1-Year limited warranty

11-404 Pollak Heavy-Duty, 4-Way, Round Pin Trailer Wiring Socket, Concealed Terminals - Metal - Vehicle End

Customer Reviews

Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket - Metal - Vehicle End - PK11404

Average Customer Rating:  4.8 out of 5 stars   (94 Customer Reviews)

Establish a secure connection between your trailer and your towing vehicle with this 4-pole, round pin, wire-insertion style socket. Zinc die-cast socket has concealed terminals to provide easy assembly and durability .


Ordered this along with the Remote Controller, however, the controller would not slide onto the 4 poles. Tried to squeeze the poles and they split leaving one side on each pole. Ended up grinding each partial pole tip so the remote could slide on it. Don't know how long they will last before I have to order another 4 prong connector. They are working fine for now.

It sounds like you were able to get this part to work for what you needed it for, however, the remote item # BDW20144B
Replacement Hand Controller for Bulldog Winch BDW10012 Trailer Winch - 4-Prong
is a replacement for the bulldog winch BDW10012 and it will plug right into the winch.
-- Etrailer Expert Sierra K - 06/22/2022


The round pin socket is good, the only issue is it is very easy to install the hookup wire upside down due to the key is not very pronounced in the socket. The socket needs a deeper master key slot.

Still working no issue again which it had a better master key slot
Michael - 02/13/2022


I've never really liked Flat-4 type connectors. Unless you leave them dangling, they usually require that you crawl under the vehicle to connect them. (...Murphy's Law dictates that this will always be when it's raining or snowing).
This Pollak 4-pole round socket, along with a Tow-Ready harness, and matching trailer connector, provides a neat, factory installed look, that's more convenient, and durable.
My orders from etrailer arrived quickly, and with great seller communication. A+


Easy installation and perfect performance. Would recommend without hesitation.


Very fast shipping


Worked perfectly I plugged it in simply plug and play. I havnt had any issues with the connections. 10/10


Quality is good but buyer beware - you must use a compatible plug, as all round 4 pins are not the same. This particular socket has two different size pins (3/1) so be sure to buy a matching plug or pick a different receptacle.

Thanks for your review and your business, Pete. I am glad you brought this up! The PK11404 is used in conjunction with PK11402.
-- Etrailer Expert Laura E - 01/09/2017


Great customer service from Caroline! Order came in two days amd earlier than expected. Exactly what I needed and at a great price!


Poorly manufactured. Fell apart after 3 months. The inside wire connection came loose and pulls out of the body of the socket. Had to rebuild the item and secure inner socket with sheet metal screws. It still works but I expected better quality and longevity.


Found this company by accident. Living outside of a large city it can take me most of a day to obtain the parts I need. This works well as I can order my parts and move on to the next project. The parts so far have come fast, as stated and packaged well for the travel to my shop allowing me to get the project done or back into service.
NOTE: Check out the etrailer videos online, They are a great resource for the beginner into the industry or the seasoned professional that wants a refresher.


Just completed the installation of this product. I'm happy with the quality and believe it will be better than the chrome one (different brand) that it replaced. As usual, "etrailer" did an excellent job of getting the product to me quickly and provided constant follow-up through delivery. They are the best in my opinion!!!


I would highly recommend changing the flat plugs with this one.


I like this Pollak brand. Their connectors always seem to work the best. I wish this 4 pole connector came with a rubber boot for the back. I couldn't find one, even at the Pollak website. I ended up taping it up really good with electrical tape.


Product is just what I expected. I'm going to use this to plug a salt spreader to the truck. The factory harness is pretty beat up so this will make plugging it in much easier. Extremely fast shipping. Great place for your trailer needs. Anything I need from now on will be from Etrailer.


Sturdy device and easy to install with the online video


After a Wisconsin winter it worked like a champ. The winters here are the test for any wiring product. This plug passed all the way.


I've used the Pollak pk11404 on a Jeep for a couple of years. The Wi. winters can be a beast on the standard flat 4 wire plugs. This plug came thru winters like a champ. I've traded cars so this 1 is for the new Chev. Great Job Etrailer


This replaces a failed one that was made of rubber and did not hold up to repeated plugging and unplugging.

It has worked very well. We sold the RV and now have the BlueOx tow bar and brake system for sale.
Jack - 05/24/2018


Product is exactly what I ordered. I received an email confirming order was placed into system.... 20 minutes later, I received an email that my order was ready for shipping!!
2 days later, I have my product!!

Awesome communication and Awesome prices.

I will be a returning customer.



It was great. We got it in barely no time and it was installed and has been working great for the past 2 weeks. Highly recommended.


great customer service


Needed to complete the connection, does require some drilling of holes for mounting screws, but makes a solid connection. Spring loaded cover also locks the connection together. Is easy to use in all weather conditions, and with metal construction is heavy duty and long lasting


Item is as described and good heavy duty quality. S&H was very reasonable and delivery to Hawaii took less than a week.

I highly recommend and will personally shop here again.


The product that I needed to repair my trailer connection was not to be found in any of our parts stores. I looked on various webs and ran across etrailers's parts. The parts that I ordered were as advertised, came to me, promptly, and I was really impressed by their packaging. I will buy from them again.


Products arrived earlier than promised. Very easy to install.
So far, they are working better than the plastic OEM products that wore out after 2 years of use.
Only possible improvement would be to include a colored wiring diagram for people who not be as knowledgeable about electricity.

Show More Reviews

See what our Experts say about this Pollak Trailer Wiring

  • Width Between Mounting Holes and Total Width of Pollak Heavy-Duty, Trailer Wiring Socket, # PK11404
    I spoke with my contact at Pollak. He stated the center to center distance between the mounting holes on the Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket, # PK11404, is 2-7/8 inches. The total width is 3-3/8 inches.
    view full answer...
  • Pin Designation on 4-Way Round Socket Vehicle End
    The Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket - Metal - Vehicle End # PK11404 will have the wires labeled in the following manner: White - Ground Green - Right Turn and Brake Lights Yellow/Red - Left Turn and Brake Lights Brown - Tail Lights I've attached a video to help with this pin out. If you are looking at the 4 pins. The bottom left is ground, the bottom right is running/tail lights, the top left is left turn and brakes and the top right is right turn and brakes....
    view full answer...
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  • Female Side Of 4-Pin Round
    We have the Pollak Heavy-Duty part # PK11404 which is considered the female plug that traditionally goes on the vehicle side but could be used on the trailer side. The trailer side male end is part # PK11409. Please let me know if this is not what you are talking about and I can help further.
    view full answer...
  • Which 4-Way Round Trailer Side Connector Fits Pollak Heavy-Duty, 4-Pole, Round Pin Socket # PK11404
    The 4-Way rounds have 2 different sizes. The connector that is compatible with # PK11404 is # PK11402. What you can do is either replace the 4-Way flat on the trailer side with this connector or you can replace the 4-Way round on the adapter you have with # PK11402.
    view full answer...
  • Distance Between Mounting Holes on the Pollak 4-Way Round Connector
    I grabbed a Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket, # PK11404, from our warehouse to measure and found the distance between the mounting holes on center is 1-3/4 inches. If you check out the picture I attached you will see that you would have to come up with a shackle type adapter to allow this connector to be used on your base plate.
    view full answer...
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  • How Should 4-Way Round Vehicle End PK11404 Be Wired
    If you are towing a vehicle with a motor home the 4-way round connections inside the vehicle end are usually as follows: Top left: Yellow wire, Left turn and brake function. Bottom left: White wire, ground wire. Top right: Green wire, right turn and brake function. Bottom right: Brown wire, tail light function. There is not an industry standard wiring diagram for the 4-Way Round vehicle end, part # PK11404, so you may need to use a circuit tester, part # 40376 if needed, to check...
    view full answer...
  • Availability of 4-Round Trailer and Vehicle Connectors that Will Accept 12 Gauge Wire
    A 3-flat is indeed a tough plug to find. It might be best to change to a 4-Way of some type. We have the Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Connector, # PK11402, that will accept up to 12 gauge wire. This is a trailer end plug. The vehicle side is the Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket, # PK11404. It, too, will accept 12 gauge wire. I have included an FAQ article on trailer wiring below.
    view full answer...
  • Is the 4-way flat to 4-way Round # 47465 Compatible with with 4-Pole # PK11404 and # PK11410
    I went and pulled the Adapter part # 47465, Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket # PK11404 and Pollak Heavy-Duty, 4-Pole, Round Pin Socket # PK11410 to see if they were all compatible and I found that they were. The round 4-way of the # 47465 is compatible with both the # PK11404 and the # PK11410. Check out the video I attached where I show this.
    view full answer...
  • Trailer Wiring Socket Recommendation for a 4-Pole Round Trailer Connector
    For a 4-pole round trailer connector and socket, I would recommend looking at the Pollack Heavy-Duty 4-Pole Round Trailer Connector, # PK11409, and the Pollack Heavy-Duty 4-Pole Round Trailer Socket, # PK11410. The connector and socket have a chrome-plated finish for corrosion resistance. I have attached a photo showing the typical wiring set up for 4-pole round trailer connectors. This should help when you are wiring the connectors to your trailer and vehicle.
    view full answer...
    Image 1 for
  • Componenets Needed to Wire 7-Way Blade and a 4-Pole Round Trailer Connector
    I would recommend the Pollak 7- and 4-Pole Trailer Connector Socket, part # HM40975. This connector would allow you to use both the 7-way connector as well as the more common 4-pole flat connector. On the other end of the bumper, you could use the Pollak Heavy-Duty 4-Pole Round Pin Trailer Wiring Socket, part # PK11404. This connector could be tapped into the wiring for the 7-way connector. This set-up would allow you to tow many different trailers, without the need for an adapter.
    view full answer...
  • Is Pollak 4-Pole Round Trailer Wiring Socket # PK11404 Compatible with Coiled Extension # HM47045
    Yes, the Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket, # PK11404, and the Hopkins Heavy-Duty Trailer Coiled Extension, # HM47045, are compatible parts. You can see a typical wiring description on the product page for the PK11404, under specs. White would be ground return, green is right turn and brake lights, yellow/red is left turn and brake lights, and brown is taillights. Essentially, there is no standard or agreed upon diagram of which function should go with which pin...
    view full answer...
  • What Type of Socket Does 4-Way Round Side of HM47043 Attach to
    The 4-way round side of the Hopkins Endurance Flex-Coil Trailer Connector Adapter part # HM47043 that you referenced would attach to a 4-way round like the part # PK11404 and would work well.
    view full answer...
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  • Recommended Adapter for 4-Way Round Trailer Connector on Motorhome
    The Custer Trailer Connector Adapter - 4-Way Round to 4-Way Flat # ADP001 will work for your 1995 motorhome with 4-Way round. The 4-Way round trailer wiring connections carry the same functions as the 4-Way flat trailer wiring connections they are just more heavy-duty, so this adapter will allow you to capture the functions you need for your trailer. The pins will fit the dimensions you gave as that is the traditional application for a trailer connector like # PK11404.
    view full answer...
  • Replacement 4 Round Trailer Wiring Socket for Roadmaster 7-Wire to 4-Wire Flexo-Coil Kit
    It sounds like you're looking for the Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket - Metal - Vehicle End # PK11404, which can be used on the toad side to replace the socket that came with your Roadmaster Diode 7-Wire to 4-Wire Flexo-Coil Wiring Kit # RM-15247. If I'm misunderstanding you and you're in need of a different part, just let me know and I'm happy to help you locate the part you're seeking.
    view full answer...
  • Compatible 4-Way Round Trailer Connector for Hopkins Flex-Coil Trailer Connector Adapter, # HM47043
    No, you will want to use the Hopkins Endurance Flex-Coil Trailer Connector Adapter, # HM47043, with 4-Way # PK11410. It is not compatible with # PK11404. Regarding the wiring configuration there is really no standard way of wiring a 4-Way round connector. But if you are looking at the front of connector PK11410 the bottom left is ground, top left is left turn/brake lights, top right for right turn/brake lights, and bottom right is running lights like in the video I have linked.
    view full answer...
  • How to Install a 7-way and 4-way # HM40975 on a Vehicle with a 4-Way Round
    We have what you need. It sounds like you have a 4-way round on your trailers like the part # PK11404 already installed on your trailer. So what you will need to do is first cut the 4-way off of your tow vehicles and then wire the wires that previously ran to the 4-way to the Harness part # PK11998. You will want to run the running light circuit to the brown wire, the ground to the white wire, the left turn/stop circuit to the red wire and the right stop/turn to the green wire. The rest...
    view full answer...
  • 4-Way Round Trailer Connection Much Smaller Than What I Can Find
    I have never seen a connection like that for a 4-way. Regardless of the pin size the slot is internal to the plug on the connection point instead of external as on current 4-Pole Round Connector # PK11404. I recommend replacing the connection with a standard size round connector # PK11404 or converting to the more common 4-flat # HM48190. The Adapter 4 Round to 4 Flat # will use the standard 4 round size connector.
    view full answer...
    Image 1 for
  • How to Wire Nissan Tow Car to Winnebago Motorhome with 4 Pin Round Connector
    Wire colors on motor homes and vehicles are not standard and vary, even between models produced in the same model year. Because this is the case you will need to use a circuit tester, item # 40376 if needed, to test the existing wires on your motor home and vehicle to determine the correct wires to splice your tow wiring to by function. Use the circuit tester and have someone in the vehicle activate each function. Once each function is located on the car and motor home label each one and...
    view full answer...
  • No Drill Mounting Bracket for Installation of a 6-Way Connector # PK11404 on a 2009 Toyota Tacoma
    Yes, we have a bracket for mounting the Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Connector, item # PK11404. The Pollak Connector Bracket for 4-, 5- and 6-Pole Trailer Connector Sockets, item # PK11627, is designed to be attached in several ways. If you like, you can attach this bracket by drilling two holes and screwing the bracket to any location you like. If you do not want to drill, there are two other mounting methods. One is to use the Plate that sticks out to the side of the...
    view full answer...
  • Testing 4-Pole Vehicle Socket to Confirm Wiring Configuration
    On the Pollak Heavy-Duty 4-Pole Round Pin Trailer Wiring Connector # PK11402 the ground pole (shown in the linked photo) is at lower-left. It is certainly possible that your vehicle socket, one like # PK11404, was wired with ground on a different pin. You will need to test the vehicle wiring to confirm so that you can wire connector # PK11402 to match. This is easy to do; all you need is some wire like # 10-1-1 to connect the battery to the contacts on the vehicle's socket. This will show...
    view full answer...
  • What Style 4-Way Round Socket Does the Custer Trailer Connector Adapter # ADP001 Fit
    The Custer Trailer Connector Adapter # ADP001 that you referenced is designed to fit 4-way round receptacles like the Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket # PK11404.
    view full answer...
  • How to Wire Up a Tow Vehicle that has a Separate 6-Way to Tow a Vehicle with a 4-Way Flat
    The easiest way to do what you need is to convert the signal on your RV's connector to a combined circuit and then install a 4-way on your RV like part # PK11404 in place of the 6-way. For that you would want to start with a signal converter like part # RM-732. You will need to wire up the RV trailer wiring just like the label of the converter recommends. You'll notice that the running lights aren't mentioned on the label, that's because it bypasses the converter and runs straight to the...
    view full answer...
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  • What Gauge are the Internal Wires of the Roadmaster RM-1064-B
    I spoke to Roadmaster and they said all 4 internal wires of the # RM-1064-B are 12 gauge jacketed wire. Depending on what you will be doing with this wire, the following parts may also be good options for add on parts as well. The Pollak Heavy Duty 4 Pole Round Trailer End # PK11402 would attach to the end of the # RM-1064-B very nicely. This would then pair with the Pollak Heavy Duty 4 Pole Round Vehicle End # PK11404. The # RM-1064-B would then attach to a junction box on the trailer,...
    view full answer...
  • Towed Vehicle Wiring Recommendations for my 2017 VW Beetle and my 2017 Chrysler Pacifica
    We have what you will need to accomplish this. You will install the Roadmaster Diode 7-Wire to 4-Wire Flexo-Coil Wiring Kit part # RM-15247 on one of your vehicles and then the Roadmaster Universal Hy-Power Diode Wiring Kit part # RM-152 along with the Pollak Heavy-Duty, 4-Pole, Round Pin Trailer Wiring Socket part # PK11404 on the other. This will allow you to use the same coiled pigtail that is included on both vehicles.
    view full answer...

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Info for this part was:

Employee Sarah L
Expert Research:
Sarah L
Employee Robert G
Expert Research:
Robert G
Employee Patrick B
Expert Research:
Patrick B
Employee Michael H
Expert Research:
Michael H
Employee Tyler C
Written by:
Tyler C
Employee Joshua S
Video by:
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