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Wiring > Wiring Adapters > Single-Function Adapter > 4 Flat > 6 Round > Plug and Lead > Tow Ready

Adapter 4 Pole to 6 Pole

Tow Ready Wiring

(26 reviews)

Code:   30637



Shipping Special

Shipping Weight: 0.8 pounds


Tow Ready Wiring - 30637

Adapter converts your 4 pole wiring on vehicle to 6 pole round connector. Additional leads for brake (blue) and power (black) can be connected to allow for electric brakes and accessories.

Wiring Harness Mount Brackets

Tow Ready # 20320

Video of Adapter 4 Pole to 6 Pole

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

Video Demo Tow Ready Wiring 30637
Tow Ready Wiring 30637 Review

Video Transcript for Tow Ready Wiring 30637 Review

Today we're going to review part number 30637. This is the Tow ready 4-Way Flat to 6-Way Round Pin Connector Adapter. Now, this adapter will convert your 4-pole wiring on your tow vehicle to a 6-hole round connector on your trailer. There are additional leads for the brake and for the power and also the white is for the ground. These can be connected to allow for electric brakes and accessories. Now, if you do have a, the 4-way right here would plug into the 4-way on your vehicle. Now, if the trailer has a 6-way and you just wanting to use the lighting functions, you can just plug in this 4-way and it would give you the lighting function.

You will still have to install this white wire with the eyelet to a big clean ground to get those functions to work. But, if you're wanting to use, I had an electric brake controller or any other 12-volt accessories, you do need to install these other 2 wires. Basically, what you would do is after you take the white wire and install it to a good clean ground, go to the blue wire. The blue wire is for the electric brakes. What you need to do, this would be routed under the vehicle using extra wire and then attach it to the blue wire on the brake controller. The black wire would be for 12-volt power.

This would have to be attached to a black wire and then routed under the vehicle and attached to the positive battery termining 00:01:24 with a 40-amp circuit breaker. Once you have that all hooked up, then you could plug in the 6-way on your trailer and get all the lighting operations, electric brakes, and still have 12-volt power. Length on this, to give you an idea of the measurement, lengthwise from the end of the 4-way to this about 15 inches in length. That should do it for the review on part number 30637. The Tow Ready 4-Way Flat to 6-Way Round Pin Connector Adapter. .

Customer Reviews

Adapter 4 Pole to 6 Pole - 30637

Average Customer Rating:  4.8 out of 5 stars   (26 Customer Reviews)

- 30637

by: Brad S08/27/2014

I purchased this along with factory wiring connector for my Chevy K10- that was a breeze to click into the factory harness. I was having issues with the wiring job from before, i cam across Etrailer and found these quick install harness to fit my needs. it took less than 15 minutes to click in to space. i mentioned before, Cheaper than the local Trailer shop and no splicing. Good quality, on time delivery, easy to install. 148960

- 30637

by: Morgan M.06/02/2012

Work perfect. This Adapter worked perfectly for what I needed. Seems to be heavy duty and durable. I'm using it for a Stock trailer to pull a horse. It was really helpful the way this site is set up. By having the customer tell them what type of plug from the Truck and Trailer, it advised me the exact plug I needed. No other auto supplier, Wal Mart or anyone I asked could get me the right plug. 42462

- 30637

by: Jeremiah03/18/2013

I used this with a Ford Ranger adapter. It hooked right up. I didn't see that it didn't have the bracket to attach to my pickup. I bought one at an auto parts store. It was easy to attach and works. The price was the cheepest I found, shipping was great. Etrailer is great to work with. I will shop here again. 71284

- 30637

by: Timothy Clifford07/19/2012

Only place I could find this hook up! Drove about $15 worth of gas going to the usual auto parts stores. No one had it. Came to etrailer, bang! Instant find (with help from a fella that put me right on the product number). Fast deal, fast shipping, exactly what I needed! 48495

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by: Ernest L.06/20/2014

I was told to check out etrailer for all my needs anything for my trailer and like WOW!!!! They actually had what I needed and shipping was fast. It works perfect with NO issues at all. Thanks guys for your help on this and I will definitely order again from you. 136748

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by: bishop3d06/19/2012

Product worked as advertised. Did not utilize the brake wiring (didn't need to for my application). If I choose to keep permanently hooked on my 04 Pilot, will require some mounting hardware since tralier hitch doesn't really have anywhere to put it. 44788

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by: Bill LaCombe05/06/2014

I had to give you this praise too! Great website! My son and I have both ordered recently! Fast, cheap shipping! Products worked AWESOME!!! Thanks! The wiring harness for his Dakota was awesome. The adaptor was even easier! 129231

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by: Danny B03/02/2012

Product is well made and came exactly as described. I placed the order on Sunday night, went with standard delivery, and it was delivered on Wednesday. Great turnaround and wonderful experience 33035

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by: Paul M,05/15/2013

Product serve it's intended purpose exactly as planned. Very pleased with the product and especially Etrailers service. Excellent communication. 80428

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by: Shane04/03/2013

Got this to go on my jeep. Installed clean and discreet. Definitely low profile and guarenteed to stay out of harms way while wheeling in our JK! 73949

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by: Mike C11/06/2011

Now I'm ready for what ever harness I come across. Plenty of room in the jack compartment for it to stay new and ready when I need it. 26638

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by: David G02/21/2013


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by: J.D.12/08/2014

Quality products and reasonable prices with a ship out time that is second to none. Thanks for the excellent service. 163769

- 30637

by: Todd07/22/2011

Exactly what I was looking for but had a hard time finding it anywhere else for such a reasonable price. 19865

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by: Dan R.09/14/2011

The only thing that would make this better is if the hitch had a convient place to install it. 23946

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by: Gus05/14/2013

Thank you for your prompt delivery. It was exactly what we needed. 80307

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by: Barney10/04/2014

Works great. Delivery was quick and product was just the ticket. 154472

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by: Richard J07/17/2012

Product arrived in a timely fashion and installation was simple. 48250

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by: Thomas Tran11/20/2013

Great product to connect to 4 pole flat from Honda Pilot 107886

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by: Scott G07/24/2013

Easy to install. Works as expected. 91267

- 30637

by: R Adams06/03/2014

High quality works great. 134138

- 30637

by: Yoshino Keech08/02/2011

products ore exelent 20896

- 30637

by: Joe11/19/2014

Just as described, 161795

- 30637

by: Rick S.11/10/2014

Just what I needed 160194

- 30637

by: Greg06/02/2011

Great product 15971

- 30637

by: bill dunne01/25/2011

fit perfect 6099


Ask the Experts about this Tow Ready Wiring
Do you have a question about this Wiring?

  • Why Does my 4-Way Connector Have 2 Wires Ran to One Prong for the Tail Light Circuit
  • It sounds like you need an Optronics wishbone wiring harness, part # A35W42B. This 4-Way has a prong that has two wires that come out of it. The reason some 4-Ways have two wires coming out of one port is because that prong represents the tail light functions for both sides of the trailer. So one wire would run to the tail lights on one side of the trailer, and the other wire would run to the other. I attached a video below that shows this product being installed onto a trailer and...
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  • 6 Prong Square on Jayco Trailer to 4 Prong Flat Wiring Color Scheme
  • The wiring colors codes for the Jayco style 6-Way connector are not readily available. I can tell you that the following colors have worked out on a Jayco trailer before. Yellow - Not determined, Green - tail light, White - ground, Red - left turn and brake, Black - not determined and Brown -right turn and brake The leftover yellow and black wires would be used for auxillary power and backup lighting or trailer brake power, whichever is needed. You would need to use a circuit tester,...
    view full answer...

  • Trailer Wiring Has 5-Wires White, Yellow, Green, Yellow/Brown, and Green/Brown
  • On a 4-Way flat trailer wiring harness, white is the ground, brown is running lights, yellow is left turn signal and green is right turn signal. It sounds like your trailer has a wishbone harness. A wishbone harness splits the running light circuit at the connector so you do not have to run a jumper from one side of the trailer to the other side. On a wishbone 4-Way connector the white wire is ground, yellow is left turn signal, yellow/brown is left side running lights, green is right...
    view full answer...

  • Adapter for a 4-Way Flat Vehicle End Trailer Connector to 6-Way Round Pin Trailer Connector
  • If you only want to use the basic lighting functions provided by the 4-Way (left/right turn, brake, and running lights) then all you will need to do is plug the 4-Way end of the Adapter 4 pole top 6 pole, # 30637, into your vehicle 4-Way. The trailer 6-Way will then plug into the 6-Way receptacle on the adapter. You will also need to ground the white wire on the adapter to the vehicle frame at a clean and corrosion free metal surface. The remaining wires (blue for electric brakes and black...
    view full answer...

  • Wiring Up a Harbor Freight 4-Way Trailer Connector and Trailer Lights
  • Lets start with the trailer connector. I can tell you what the functions are so it will be easy to connect to the lights once we determine their functions. On a 4-Way, you will have one pin that is covered. That is the ground. Right next to it is the running light pin. Then the left turn/brake light pin. And the last pin is right turn and brake lights. Now, on the lights, since the common wire on both sides is red, I am inclined to believe this is the running light wire. What you...
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  • Adapter to Connect 4-Way on Vehicle to 6-Way Round on Trailer
  • A vehicle end wiring harness using a 4-Way Flat connector should have 3 female plugs and 1 male pin. A matching 4-Way Flat trailer connector would have 3 male pins and 1 female plug like on the Tow Ready Adapter 4-Way Flat to 6-Way Round, part # 30637. The # 30637 adapter is designed to plug into a 4-Way Flat on a vehicle and the 6-Way Round on the other end, with the male pins, will plug into a 6-Way Round on the trailer that has 6 female plugs. I am including a link to a FAQ page...
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  • Some Trailer Lights Are Not Working But Running Lights and Marker Lights Are Not
  • You are probably on the right track in thinking a grounding issue is at fault. Often if a trailer has a weak or marginal ground connection it will be able to pass enough current for lower current draw lights (such as the turn signals that are not on continuously) but not enough for the always-on running and marker lights. I suggest you recheck the security of the ground connections. You can try sanding off paint (or rust) at the spot where your ground wire ring terminals are attached....
    view full answer...

  • What Adapter is Needed For Borrowed Trailer Pulled By Mercedes-Benz ML350
  • It sounds like you have a 7-way connector on your ML350. If the trailer you plan on towing has the female version of your connector then you will not need an adapter. The other possible situation is you have the 7-way male connector on your ML350 and the trailer has a 4-way. If this is the case then Hopkins # HM47365 should work. In order to determine exactly what will work with the trailer, we will need to know what connector is used on the trailer. Not all trailer companies use the...
    view full answer...

  • Brake Controller Wiring on a 2002 Ford F-250
  • For the Pilot 2-6 Brake Electronic Brake Controller - Time Delayed # 80550 you can use Universal Brake Control Wiring Adapter # 20260. If you have factory 7-Way the only part needed to install a brake controller is the brake controller and wiring adapter. Usually the factory will already give you a brake control adapter that connects to the brake controller and plugs into the dash. If you do have this harness you can also use it with the Pilot. The OEM plug is on the drivers side, usually...
    view full answer...

  • Availability of a 4-Way Flat to 6-Way Round Trailer Connector Adapter
  • We actually have a pre-made 4-Way to 6-Way round adapter that you could use if you wanted to, # 30637. For this you would plug in the 4-Way on the vehicle to the 4-Way on the adapter, ground the white wire to the frame of the vehicle, and tape up the other 2 wires on the adapter if those functions are not needed (if you just needed lighting functions). To make your own you would need a 4-Way trailer end connector, like # HM48110, and wire the blunt cut bare wire ends to the 6-Way round...
    view full answer...

  • Trailer Hitch, Drawbar, Hitch Ball, and Trailer Wiring Recommendations for a 2008 Jeep Commander
  • I can certainly point out everything you will need to tow the boat with your 2008 Jeep Commander. First, you will need a hitch. There are several available but I recommend going with a Class III hitch rated for weight distribution because you never know what you might be towing in the future. I would go with Hidden Hitch Trailer Hitch, # 87752. This is a Class III, 2 inch trailer hitch, capable of 500 pounds tongue weight capacity and 5,000 pounds gross trailer weight. When used with...
    view full answer...

  • Wiring For the 2011 Jetta TDi Sedan for Towing a Trailer with Reverse Lights and Electric Brakes
  • The bypass that you mentioned is most likely the power wire that allows this harness to draw power directly form the vehicle battery and eliminate the possibility of overloading the sensitive circuitry and computers on your 2011 Volkswagen Jetta. The CURT wiring harness, # 56146KIT, is designed to work with your vehicles electrical system and does have the separate 12 volt power wire to protect your vehicle wiring. To tow a trailer with reverse lights you would need to use the Universal...
    view full answer...

  • Availability of Adapter For Connecting 6-Way Round on Trailer to 4-Way Flat on Tow Vehicle
  • I would recommend to use the Tow Ready 4-Way to 6-Way Adapter, part # 30637. If you only want to use the basic lighting functions provided by the 4-Way (left/right turn, brake, and running lights) then all you will need to do is plug the 4-Way end of the # 30637 adapter, into the vehicle 4-Way. The trailer 6-Way will then plug into the 6-Way receptacle on the adapter. You will also need to ground the white wire on the adapter to the vehicle frame at a clean and corrosion free metal surface....
    view full answer...

  • Availability of a 6-Round to 4-Flat or 7-Way to 4-Flat Trailer Connector for an RV
  • It sounds like what you want to do is to pull a trailer with a 4-Flat with an RV that has a 6-Round. 6-round connectors are not too common on RVs, but more common on horse trailers. Double check to see if you actually have a 7-Way blade style connector. A lot of connectors look alike. I have included a link to a Trailer Wiring FAQ article that, in part, discusses the various style connectors starting about 1/4 of the way down the page. To convert a 6-Round to a 4-Flat, you can use a...
    view full answer...

  • Adapter 4 Pole to 6 Pole # 30637 Recommendation and Wiring
  • It sounds like your trailer has a 6-way round connector and your truck has a 4-way flat connector. You could use an Adapter 4 Pole to 6 Pole, part # 30637, like what you referenced. If all you needed was tail light functions on your trailer you would simply mount the 6-way round of this adapter on your vehicle and secure the other wires up and out of the way, and then plug the 4-way from your truck into the 4-way of this adapter and then plug your trailer into the 6-way and you would...
    view full answer...

  • Recommend Hidden Hitch, 6-way Wiring, and Other Needed Accessories For 2009 Nissan Murano
  • I can recommend a hitch, wiring, and additional accessories that you will need to complete your towing setup on your 2009 Nissan Murano, but all of our hitches and wiring are sold separately. The hitch you selected, Hidden Hitch Trailer Hitch, part # 87486 does not have hidden wiring included. For a hitch, I would recommend the item you selected, Hidden Hitch Trailer Hitch, part # 87486, as it is a Class III Hitch with 2 inch receiver. For wiring, you will need Tow Ready Custom Fit...
    view full answer...

  • Wiring a 5 Wire Volvo Semi Tractor to a 4 Wire Gooseneck Trailer
  • To make the 5 Wire system on the Semi work with the 4 Wire system on the gooseneck trailer you will need to use a converter. The 4-Pole Hardwire Kit with Converter (Includes Tester), item # 119178KIT will provide you with a 4-Way connector that is converted to the 4 wire system on the trailer. You would then need to use either the Adapter 4 Pole to 6 Pole, item # 30637, or the Adapter 4 Pole to 7 Pole, item # 30717, to complete the conversion to the style of connector that is on the gooseneck...
    view full answer...

  • Troubleshooting Plug and Play T-Connector Trailer Wiring Harness Not Working on a 1992 Toyota Pickup
  • As long as your vehicle is a 1992 Toyota Pickup and not some other model like a T100 pickup, you have the correct wiring harness. There are two possibilities for the symptoms you are describing. A ground issue or a short between the taillight circuit and turn signal circuits. Because there would need to be a short between both the left and right turn signal circuit and the ground I would think that would not be the issue, unless the converter box has been shorted out. Since you have...
    view full answer...

  • Installation of Wire Connection on Vehicle to Recharge or Power Trailer
  • You will need to run a fused wire, item # 31827, from the vehicle battery to the vehicle trailer connector that matches the trailer connector on the trailer that you want to charge the battery on and power. You can select the proper vehicle end to connect to your trailer from our (see link) trailer connectors page. If you have the 6-way round connector the black, center pole, wire will run to the power wire you install.
    view full answer...

  • Troubleshooting Brake Light on Trailer Towed by 1998 H-D Road King and 2003 Ford Crown Victoria
  • Because the 2003 Crown Vic uses a separate bulb in the tail light assembly for the turn signals, a tail light converter is needed. If the 4-pole you have does not have a converter, and its simply been tapped into the turn and running light circuits, it would explain why the brake lights on any trailer you connect to the vehicle are not working. You can easily test this using a circuit tester like part # 40376. Attach the alligator clip on the tester to the ground pin on the connector (fed...
    view full answer...

  • Wiring A 2008 Toyota Highlander for Towing a 1996 Flagstaff Cobra Camper with 6-Way Square Connector
  • Jayco uses a different wiring code than most, so in all likelihood, it will not work. I would just cut off the 6-Way square, tape off the brake and battery wires, and connect the 4 wires to a new 4-Way flat connector like part # 9653P. A better solution may be to install a more common 6-Way Round trailer connector on the vehicle and trailer. You could use the Pollak 6-Pole, Round Pin, Trailer Wiring Connector, item # PK11604, on the trailer end and a 4 Pole to 6 Pole Adapter, item #...
    view full answer...

  • Adapting Motorcycle with 4-Pole to Trailer with 6-Way Connector
  • You will need a converter/adapter when connecting different wired vehicles. Depending on how your vehicle and trailer are wired we have three 4 to 6 wire adapters. Adapter 4 Pole to 6 Pole # 30637 Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter # 37175 If your trailer has brakes you will need a brake controller and for a motorcycle you will need a model that has time delay functionality. I would recommend the Activator II by Draw-Tite, part # 5500. This will work with...
    view full answer...

  • Adapting a 4-Way Flat Trailer Connector on 2011 Toyota Tacoma to 6 Round on 1983 Coleman Camper
  • Since your truck has a 4-Way flat connector and the trailer has a 6-Way round, adapter # HM47320 will not work. It is made to go from a 6-Way round on a vehicle to a 4-Way flat on a trailer. What you need is an adapter like # 30637. Your 4-Wway will plug into the adapter and you will need to ground the white wire to the truck frame. The other two wires on the adapter are black for 12 volt power and blue for electric brakes. If you do not wish to use these functions then you can tape...
    view full answer...

  • Availability of a Replacement Jayco 6-Way Trailer Side Connector
  • Jayco is the only manufacturer that uses that type of 6-Way connector. We do not have a replacement that is going to work. Since yours is broken this is the perfect time to install a 7-Way connector on the trailer so you do not have to mess with various adapters. If you do not want to change to a 7-Way on the trailer then you would need to get a replacement trailer side Jayco 6-Way from Jayco. But to add a 7-Way RV style connector to the trailer you can use something like # H20042. You...
    view full answer...

  • Vehicle Connector Needed On my 2005 Chrysler Pacifica to Use a Trailer Connector Adapter # TC-129
  • There is a way to wire up your 2005 Chrysler Pacifica so that you could use your Trailer Connector Adapter, 6 Pole to 5 Pole, 4 Pole and Cigarette Lighters, part # TC-129. However, you could not accomplish that using a Pollak Heavy-Duty, 7-Pole, Round Pin Trailer Wiring Socket - Vehicle End, part # PK11720. The reason the # PK11720 would not work is because it is a 7-way round vehicle connector, and the # TC-129 is actually a 6-way round connector on the side that plugs into the vehicle...
    view full answer...

  • Mounting Bracket for Tow Ready 4-Way to 6-Way Trailer Connector Adapter, 1998 Lincoln Continental
  • There can be some bracket/connector compatibility issues if the two components are of different manufacturers. Some sockets will not physically fit inside of some brackets. For the Tow Ready adapter # 30637 (20320) you would use bracket # 118137, but you would not attach it directly to the trailer hitch. What you would do is use short bracket # 18140 or long bracket # 18136, attach it to the hitch and then attach bracket 118137. Drilling into the hitch will void its warranty and can...
    view full answer...

  • Troubleshooting No Turn or Brake Lights on a Cargo Trailer
  • The brown wire that is running to both the left and right side of your trailer is the tail light circuit. The green wire that is on the right side is the stop/turn circuit and the yellow wire on the left is the stop/turn for that light assembly. The best place to start when troubleshooting wiring problems is to start at the trailer connector on your tow vehicle and test the poles of the connector to confirm the problem is on the trailer or the vehicle. Check out the video I attached...
    view full answer...

  • Wiring a 4-Way to a 6-Way on a 2004 Tacoma Pickup
  • When you plug in your properly functioning 4-way connector to the adapter the yellow, green, brown and white wires should function properly through the 6-way connector. You will then need to connect the black 12 volt power and the blue trailer brake wires. The black wire is the battery lead and is ran to the positive terminal of the battery for charging the battery of the trailer. The blue wire is connected to the blue wire supplying power to the brakes from the brake controller if your...
    view full answer...

  • Should Adapter 4 Pole to 6 Pole, # 30637 Have Constant 12 Volt Power Even With the Key Off
  • I spoke with my contact at Tow Ready, and he stated that the Adapter 4 Pole to 6 Pole, # 30637, will have power at the 12 volt pin all the time if it is connected directly to the vehicle battery. This will not put a drain on the battery unless something is connected to the harness drawing power.
    view full answer...

  • Converting 4-Way Flat on a 2005 Honda Pilot to a 5-Way or 6-Way Round Trailer Connector
  • If the trailer does have a 6-Way round then you can use adapter # 30637. This will give you the basic light functions but unless you connector the other wires on the adapter and use a brake controller you will not be able to use the trailer brakes, if equipped, or provide 12 volt power to the trailer. The white wire on the adapter must be connected to the vehicle frame. The black wire on the adapter connects to the positive terminal of the vehicle battery via a 40 amp circuit breaker...
    view full answer...

Info for this part was:

Expert Research:
Michael L

Expert Research:
Robert G

Expert Research:
Michael H

Expert Research:
Jeff D

Expert Research:
Jameson C

Expert Research:
Lori W

Expert Research:
Jeffrey L

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