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Hopkins Knockout Adapter for 4-Way Flat Trailer Connector

Hopkins Knockout Adapter for 4-Way Flat Trailer Connector

Item # HM47605
Our Price: $8.20
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Trailer Wiring
Shipping Weight: 0.16 lbs
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Keep your 4-pole flat trailer connector accessible with this adapter that lets you mount the connector in a 6-way round bracket (sold separately) or in a 1-1/4" diameter hole. Great Prices for the best trailer wiring from Hopkins. Hopkins Knockout Adapter for 4-Way Flat Trailer Connector part number HM47605 can be ordered online at or call 1-800-940-8924 for expert service.
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  • Reviews (83)
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  • Videos (1)
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Hopkins Trailer Wiring - HM47605

  • Trailer Connectors
  • Vehicle End Connector
  • 4 Flat
  • Plug Only
  • Hopkins

Keep your 4-pole flat trailer connector accessible with this adapter that lets you mount the connector in a 6-way round bracket (sold separately) or in a 1-1/4" diameter hole.


  • Adapter plugs into your vehicle's 4-flat trailer connector so that you can mount the connector in a 1-1/4" diameter hole
  • Versatile installation
    • Mounts in a 6-way round bracket (sold separately)
    • Can replace 1 of the vehicle's license plate lights
  • Dust cover keeps out dirt and water
  • Durable PVC construction

47605 Hopkins 4-Pole Flat Knock Out Adapter

Installation Details HM47605 Installation instructions

California residents: click here

Video of Hopkins Knockout Adapter for 4-Way Flat Trailer Connector

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

Video Transcript for Hopkins Wiring - Trailer Connectors - HM47605 Review

Today we'll be reviewing part number HM47605. This is the Hopkins Knockout Adapter for a four-way flat trailer connection. This adapter is going to plug in to your vehicle's four flat trailer connector so that you can mount the connector in an inch and a quarter diameter hole. It's a very versatile installation. This will mount in a six-way round bracket, which is going to be sold separately, part number HM48605. It can also replace one of the vehicle's license plate lights. On this side here we have the dust cover that's going to help keep out dirt and moisture. It simply just fits over the four flat connection, providing a nice tight, secure fit. This is made from a durable PVC construction so it's going to be very strong, very durable and again, that dust catcher's really going to come into play when it comes to keeping out dirt and moisture. That's going to do it for today's review of part number HM47605.

This is the Hopkins Knockout Adapter for a four-way flat trailer connector. .

Customer Reviews

Hopkins Knockout Adapter for 4-Way Flat Trailer Connector - HM47605

Average Customer Rating:  4.8 out of 5 stars   (83 Customer Reviews)

Keep your 4-pole flat trailer connector accessible with this adapter that lets you mount the connector in a 6-way round bracket (sold separately) or in a 1-1/4" diameter hole.


I am very pleased with the products and service provided by
The 4-way Curt trailer hitch wiring connector and Hopkins Adapter for my 2015 Honda Pilot were easy to install with the clear and well illustrated directions. They are performing as advertised with no additional troubleshooting required. The quality suggests that they are durable and will last for at least as long as I own the vehicle. I currently tow boat trailers. The car came with the OEM trailer tow bar (hitch) and basic internal trailer wiring. The parts were just what I needed to complete the package.
[I suggest you include a note to install the provided 10A blade fuse in the holder on the S3 harness in the installation instructions]

Charlie F.


I am very happy with your product and expect I will continue to be.


A great adapter for a clean practical look on plastic bumper moulding.
Quick and easy online ordering.


I used this device to tidy up a recent hitch and wiring install on my Volvo wagon. I ran the receptacle out the bottom of the car and just zip tied it to the hitch. It looked OK, but I wanted something cleaner that didn’t involve attaching a bracket to hold the 4-pole connector. After a few minutes of searching I found this device. All I had to do was buy a 1.25” hole saw for my drill and the rest was easy. Drilled through the plastic fascia on the underside of my bumper. I think it looks great! Attached are before/after pics. Another great experience with!!!


I used this to make an easy trailer connection for my wife's CanAm Spyder. It works perfectly! It was easy to install and it was "Plug and Play". Thank you for providing this product.


Quick install, just drill a hole and pop it in. 4 stars because I don’t like how it sticks out so far and is noticeable. The manufacturer may consider designing one that is recessed in farther even if you need to drill a bigger hole. Love etrailer !


Great quality, will work for my application. I was worried I would have to make an odd hole, but cutting a circle with a hole saw will work perfect.


Worried as first because the picture with instruction showed an adapter and I had a curved surface on my GMC Terrain at the mounting point. Worked great and did not een have to take the ld pigtail off.



Perfect! I did sell the Terrain and the new owner thought the trailer wiring looked like it was from the factory. Kudos, Etrailer...


Exactly what I needed to clean up the installation of my trailer wires on my 1995 Ford F150.



Excellent! It is still perfect.


Great service. On time and accurate!


Installation photos


I'm writing from Canada. I ordered the Curt receiver trailer hitch, and customized wiring harness. Although it took a while to get here, the product was exactly as specified, installed quickly with good instructions. One word of advice, use at hoist to install the hitch, laying on the garage floor and tightening the bolts to specs. just about did me in, maybe I'm getting to old. The wiring harness was a breeze to put in with excellent instructions. Good product and service.


Worked great. Needed to locate flat 4 through to my hitch electrical mounting plate, fit perfect and great prive



Great product, no issues.


Worked perfectly. Unfortunately ran into a deer two months ago and.dont have the vehicle now


Just installed it today 8/21/21 on bumper sure makes it easier to get to I don't have to reach under bumper to hook up


great product. just what I needed to get the wires neat and out of the way.


Quick delivery and works as expected.


Thanks! Great idea! 1979 Ford F150 4X4


I added this to my 2002 Ram 1500. I drilled a 1.25" hole in the plastic plate next to the license plate and mounted it there. It was easy to install and makes my wiring harness easy to access. Good quality.


I am always pleased with how etrailer treats my orders. I am angry with myself for ordering the bracket for the socket attachment ( realized that I already had one), but the order was filled the day I would have canceled--so I just let it go.


Excellent service, easy ordering process. Will definitely use entrailer in the future.


It might have fit something, but not my truck bumper. The hole for the license plate light was way bigger than the adapter.


Nice solid chunk of plastic. Didn't come with any grease, but that's ok. I'm using a small amount of a very thick silicone plumbers grease to keep the connections from corroding & adhesive lined shrink tubing on the inner connection, because that's going to be out of reach inside a plastic bumper cover


Decided for now not to install product I changed my mind and wanted to stay with the clean rear bumper cover with the Ecco hitch hidden trailer hitch.


Exactly what I wanted.


Ordered on line Hitch, Harness and associated items. Within a couple of day the large box was delivered. Installation Videos a plus.
Install and pictures next, when it stops raining!

Show More Reviews

See what our Experts say about this Hopkins Trailer Wiring

  • Can I Drill A Hole In My Bumper To Install Hopkins # HM47605?
    You can do that if you would like. If it were me, I would just get the Hopkins mounting bracket # HM48605 so I didn't have to drill a hole in my bumper. If you are wanting to install # HM47605, using the bracket is the best way to do it!
    view full answer...
  • Compatible Mounting Bracket for the Hopkins Adapter for 4-Way Flat Connectors part # HM47605
    The Hopkins Knockout Adapter for 4-Way Flat Connectors part # HM47605 that you referenced is designed to let you mount a 4-way in what was once a 6-way round bracket like Hopkins Mounting Bracket part # HM48605.
    view full answer...
  • Availability of Cover for 4-Way Trailer Wiring Connector
    Sounds like you are looking for the Curt 4-Way Flat Wiring Connector Cover # C58200 which is a universal style 4-way dust cover that can be closed when not in use to protect the connector.
    view full answer...
  • Can Hopkins 4-Way to 4-Way Adapter Work With Draw-Tite trailer Connector Mounting Box
    The Hopkins Adapter, part # HM47605 is actually a 4-way to 4-way adapter. I pulled the Draw-Tite Mounting Box, part # 18159 from our warehouse, and the HM47605. The 18159 has a 2 inch diameter hole, so the HM47605 will not work with this box, but we do have a mounting bracket that will work. I recommend the Hopkins Mounting Box, part # HM48605. This bracket comes with the mounting hardware and will work with the HM47605 adapter and 4-pole round, 5-pole round, and 6-pole round trailer...
    view full answer...
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  • Availability of a 4-Way Trailer Wiring Harness with Mounting Bracket for a 2011 Chevy Colorado
    If your 2011 Chevy Colorado has a 4-Way flat, or, you install a 4-Way flat like # 118301 that you have referenced, you may be able to use 4 Pole Knock-Out Adapter, # HM47605. I went out to the warehouse to measure this part and it is 1-5/8 inches in diameter at the largest point which would be a little larger than a quarter. You would just need to route the 4-Way harness through the back of the plug, connect it to this adapter, and then mount the adapter into the hole. You will just need...
    view full answer...
  • Can 4 Pole Knock-Out Adapter # 30601 Install on Tow Vehicle and Trailer
    The 4 Pole Knock-Out Adapter # HM47605 could install on either the vehicle or trailer side of the wiring. Since it has each style of connector on either side of it you could easily use it on a trailer or a vehicle. It's designed to mount in a 6-way round bracket like the part # RM-910030-5 which can easily be mounted on either a trailer or tow vehicle in any 1-1/4" hole or it can replace one of the vehicles license plate lights.
    view full answer...
  • Dimensions of the Hopkins Trailer Hitches 4 Pole Knock-Out Adapter
    The 4 Pole Knock-Out Adapter, item # HM47605, is 1-1/2 inches overall diameter and has a mounting flange of 1-1/4 inches diameter. The locking tabs are for connecting to the knockout hole are 1-3/8 inches wide and 3/8 inch thick. These are usually used to mount in the 6-way trailer mounting bracket, item # RM-910030-5.
    view full answer...
  • 4-Way Flat Wiring Connector For Hopkins Knockout Adapter On Dump Trailer
    You can use the Hopkins Wiring Harness # HM48035 to connect to the Hopkins Knockout Adapter # HM47605. This has 4 wires 48" long that you will be able to wire in using the Heat Shrink Connectors # DW05744-5. Since your original only has 3 wires you will need to connect the white wire to a good ground connection since the previous must have broke off.
    view full answer...
  • How To Mount 4-Way Connector To 2020 Mazda CX-5 With Trailer Hitch Receiver
    Absolutely! Starting with the harness I recommend the Tekonsha T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118746 which is a plug and play harness confirmed to fit your 2020 Mazda CX-5. I included an installation video of the harness, but you will need to do it slightly different. You will need to cut a slot in one of the grommets in the floor of vehicle, allowing the harness to pass through underneath the vehicle. Then to mount the harness you can use the Curt Easy...
    view full answer...
    Image 1 for
  • Recommended 4-Way Trailer Connector Mount for Hidden Crossbar Trailer Hitch
    The Draw-Tite Max-Frame Trailer Hitch Receiver - Custom Fit - Class III - 2" # 75600 for your 2018 BMW X5 does not have a designated mounting location for your 4-way trailer connector. So, for the ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit # 119250KIT which is a confirmed to fit option. You can run the 4-way connector out the same bumper hole as the hitch or create a separate hole. My recommendation is either use the Hopkins Knockout...
    view full answer...
    Image 1 for Image 2 for
  • Mounting 4-Way Wiring Harness to Front of Flat Towed 2020 Jeep Gladiator
    For your 4-way wiring harness on the front of your 2020 Jeep Gladiator, I recommend using the Mounting Bracket 4-Pole Flat # 18144 with # C57202, or the Hopkins Fold-Over Mounting Bracket for 4-Way Flat Trailer Connector # HM48595. One more option is the # HM47605 combined with # HM48605.
    view full answer...
  • Options for Mounting Dealer Installed Trailer Connector on 2008 Subaru Outback
    To mount a connector, I like the 4 Pole Knock-Out Adapter, part # HM47605 with brackets # RM-910030-5 and # C57202. The # C57202 bracket would attach to your hitch using the included pipe clamp, bracket # 118137 would attach to it, and the Knock-Out Adapter would mount into the hole in the bracket. Your existing connector would plug into the rear of the adapter. The adapter includes a cover that fits over the connector to protect it from the elements.
    view full answer...
  • Recommended Mounting Bracket For Attaching 4-way Connector to 2020 Jeep Cherokee
    To attach the Mounting Bracket 4-Pole Flat # 18144 you purchased to the Curt Trailer Hitch # C13395 you have installed on your 2020 Jeep Cherokee I recommend going with the No-Drill Mounting Bracket Long # 18136. You will be able to attach it to crosstube pointing towards the ground to clear the bumper of your Jeep and then bend it so that the # 18144 can be installed in the correct orientation. Another option is going with the # HM47605 which you would drill a 1-1/4" hole in the bumper...
    view full answer...
  • Recommendation For Clean Installation of Mounting Bracket for 4-Way Vehicle Connector
    For your 2011 Ford Explorer the Tow Ready No-Drill Short Bracket, part # 18140, the Mounting Bracket part # RM-910030-5, and the Tow Ready 4-Way Knock-Out Adapter, part # HM47605, that you have referenced would make a good, clean installation of the 4-Way connector on your vehicle. Another suggestion is the Tow Ready Bracket # 18140 with the Tow Ready Mounting Bracket, part # 18144.
    view full answer...
  • Mounting Options for 4-Pole Connector on 2010 Mazda CX-9
    I have just returned from the warehouse and have looked at the actual hitch. The hitch does feature the mounting plate and is exactly as shown in the photo. The easiest method would be to keep the connector in the cargo area until needed. When you are towing, you can run the wire out the rear door and close the door on it. The weatherstripping around the rear door is thick enough that the wires will not be damaged, as long as you avoid the area around the latch. This method provides the...
    view full answer...
  • 4-Pole Trailer Connector Mounting Options for 2009 Ford Flex
    The Draw-Tite # 75679 would be great choice. For the trailer wiring harness, I'd recommend the # 118472 T-1 connector. I have two suggestions for how to attach the 4-pole connector to the vehicle. You'll need a long no-drill bracket, part # C57202, as well as the # 18144 mounting bracket. The 4-pole will push into the mounting bracket from behind. Your other option would be to use the same # 18136 bracket, along with the # RM-910030-5 bracket. You'd then use a # HM47605 knockout adapter....
    view full answer...
    Image 1 for
  • Mounting 4-Pole Connector from Curt Connector Part # C56332 on 2011 Hyundai Veracruz
    The 4-pole connector at the end of your trailer wiring harness can certainly be zip tied, but using an installation bracket like part # 18144 along with a no drill mount like part # 18140 is recommended for a clean looking installation. On my wifes KIA Sedona, I used the no drill mount, part # 18140, the bracket, part # RM-910030-5 and the knock out adapter, part # HM47605. Your existing 4-pole would plug into the rear of the adapter and would make the most professional looking installation,...
    view full answer...

Do you have a question about this Trailer Wiring?

Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Jameson C
Expert Research:
Jameson C
Employee Jeffrey L
Expert Research:
Jeffrey L
Employee Cole B
Installed by:
Cole B
Employee Tammy D
Written by:
Tammy D
Employee Alexander C
Updated by:
Alexander C

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