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7-Way Molded Trailer Wire Connector - 3' Long

7-Way Molded Trailer Wire Connector - 3' Long

Item # H20042
Retail:$35.49
Our Price: $31.89
You Save: 10%
Trailer Wiring
Shipping Weight: 1.03 lbs
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Great Prices for the best trailer wiring from Hopkins. 7-Way Molded Trailer Wire Connector - 3' Long part number H20042 can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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Hopkins Trailer Wiring - H20042

  • Trailer Connectors
  • Trailer End Connector
  • 7 Round - Blade
  • Plug and Lead
  • 0 - 5 Feet Long
  • Hopkins


Trailer Connector RV Style 7-Way Blade with 3' lead

  • Pre-wired 7-Way Trailer Connector
  • Measures 3 feet long including connector
  • Wire gauges:
    • 14-Gauge - red, brown, green, and yellow
    • 12-Gauge - blue
    • 10-Gauge - white and black


Wiring Code
Molded Connector Function Usual Trailer Wire
White Wire Ground White Wire
Red Wire Left Turn and Brake Yellow Wire
Brown Wire Right Turn and Brake Green Wire
Green Wire Tail Lights Brown Wire
Blue Wire Brake Power Blue Wire
Black Wire 12 volt (hot lead) Black Wire
Yellow Wire Aux. -



20042 7-Way Molded Trailer Wire Connector, 3' Long

Installation Details H20042 Installation instructions


California residents: click here


Customer Satisfaction Score:


Customer Reviews

7-Way Molded Trailer Wire Connector - 3' Long - H20042

Average Customer Rating:  4.6 out of 5 stars   (188 Customer Reviews)


by:

I've had this in use for over a year and they don't build them like they use to. I use this on a gooseneck trailer and the piece of plastic behind the spade connector for the clearance lights and brakes has melted, allowing the spade connector to lose contact with the plug on the pickup. So the lights would cut off in the middle of the night and would have to wiggle the connection till I could fix it. I have an older Hopkins plug and never had this problem.

To fix the problem I ended up putting pieces of thin copper wire behind the spade and have done it twice since the plastic melted a 2nd time and once again the trailer clearance lights would quit working. Attached are before and after pictures.



by:

The product works great but the color coding is off compared to the colors on the trailer. I started hooking this up matching all of the colors.( Red on Red, Black on Black, etc.) When I plugged in the trailer in it blew a fuse. So I got online and found out that the Hopkins wiring is different then normal trailer wiring. Overall it works great but the colors should match to make it easier to hook up.

Etrailer Expert

Laura E.

7/22/2017

To ensure that your trailer connector is wired properly, we recommend using a circuit tester to match pins by function. Because wire colors can vary, they are not as reliable for determining functions. Improperly connected wiring can blow a fuse or cause damage to electric components. For more information, check out this helpful article:



by:

After a year doing its job well.



by:

These plugs are made so anyone could change them.



by:

These connectors are of very high quality and make for a professional installation and appearance when used with LE$D lights and Dexter brakes. The different color of the wiring is a very minor obstacle. Using the wiring junction box really enhances the installation of the connector.

Lwal

5/27/2015

Connector is still working very well and expect to get unlimited years of service from the connector.



by:

Made nicely perfect length for my trailer. The trailer I'm using it on is only a 2 place enclosed snowmobile trailer that comes with your standard 4 flat I was tired of using adapters so I changed to this plug.

Jim B.

9/24/2014

That is exactly why I just ordered two pigtails. I am converting my 4 wire flat to a 7 pin and a 6 pin to a 7 pin. tired of trying to find adapters. I have 5 different trailer types and they will all have 7 pin when I am finished converting them.



by:

I bought an adjustable Curt receiver and my trailer wiring ended up being a few inches to short, it was tight to begin with. I was going to buy an extension but they were around 7' long, which was to long for my needs. I chose this and wired it up the other day and it works great so far. Make sure you have the RV blade type like this connector not the pin type or it won't work obviously. As mentioned in other reviews, the wiring may be color coded different on your trailer, so be mindful of that or you'll be re-doing the connections. It looks like a sturdy and well built sealed connector, so it should last for years and it was reasonably priced.

Etrailer Expert

Rachael H.

6/20/2018

We always recommend to test by function before connecting any wiring using a circuit tester like part # 3808. I have also included a link to one of our help articles that shows the different wiring configuration options.



by:

As with everything I have ever bought over the last 10 years from etrailer, never question the quality and service,they have always been there with great tech advice, fast shipping, and fair pricing.



by:

Wired to my Lance Camper harness to avoid having the Lance custom socket in the bed wall when I upgraded my truck. I had to run an 8 ga 12v source from the truck battery to the rear of the bed to supply lots of 12v power for the camper fridge. I didn't use the weak 12v supply from the stock truck trailer connector.



by:

These connectors were high quality by a known manufacturer. I could have bought them locally but I wouldn't have gotten the expert advice and detailed information that I was able to get from eTrailer!. I talked to several people and each one was very knowledgeable. When the parts arrived, it surprised me because they came so quickly! I would readily order from them again if I needed more trailer parts. I used these connectors to adapt a Minn-Kota trolling motor to my fishing kayak and have attached some pictures showing it installed.



by:

You get exactly what is pictured. The 12v power and Ground (black and white) are 10 gauge, the "Aux" (which is red on this harness and purple on the ETBC7 vehicle wiring kit) is 12 gauge, and the other 4 wires are 14 gauge. The 3' length is measured from the face of the plug to the stripped ends of the seperated wires.



by:

Wire color scheme was totally wrong for my Tundra, it’s a poor fit in the socket and it’s a touch too short. When I first hooked it up I had my running lights as blinkers and my reverse lights controlling my brakes. AVOID

Etrailer Expert

Mike L.

7/8/2019

There is more than one accepted wiring color code, which is why we identify the wire color and each wires function in the product description above.

Daniel

7/7/2020

Color schemes aside, this connector is intermittent after one winter. No physical damage can be seen but the cable needs to be bent a certain way for connection. Still 1 Star.



by:

After having our extension cable stolen and realizing the plug on the trailer was worn out and due for replacement, I decided to repair the end by adding a 3 foot pigtail. This accomplished both goals of adding cable length and replacing the plug end.
I used dielectric grease, butt crimp connectors and shrink tube to seal out the elements. Great product....



by:

Wow. Very heavy duty product at a reasonable price. I purchased this for an extension harness for my pickup because the connector on the truck is located way off to the side of the hitch. I expect this product to outlast my pickup.



by:

It's been working out for me I have two of them on my trailers



by:

Just installed the 7-way molded 3' trailer connector on an older Wells Cargo Inline Snowmobile Trailer and it fit perfectly. The molded end is going to work great keeping out the salty mist from our Wisconsin highways. The wire colors don't match trailor wiring standards, but the color key code on the web site was extremely helpful. With there fast and prompt shipping, I will be using etrailer.com from now on. Thanx



by:

Product worked fine for what I needed. Plug on my tow vehicle was further away from the ball than it was on my old one. Trailer pig-tail was not quite long enough to provide slack for turns. I put the other end on this pig-tail and extended the trailer pig-tail. Worked great.



by:

Don't waste your time and money on this product. The pig tail was wired wrong so the larger gauge wires for things like 12v constant ground and the trailer brakes were on the smaller gauge wires and when the right turn signal was on it energized 4 other wires. I figured I would just re-arrange the wires in the pig tail and investigate why the right turn signal energized so many wires and to my surprise the plug was not accessible because it was molded around pig tail.



by:

This is a well built product. The only concern that i have is that 3 of the wires are on the wrong circuit, even according to Hopkins' wiring diagram. The red, brown, and green are on the wrong circuits. Still usable as all are 14 gauge wires. All others are correct. Good product otherwise.



by:

Hard right turns with new truck pulled out camper electric connector just enough for some of the functions not to work. This fixed that problem. Needed some wire ends to make neat connections in the etrailer connection box. Used large zip ties instead of drilling to connect the box to trailer frame.



by:

Great connector, Holds up to years of daily use. Always had problems with the wire it yourself type connectors holding up to commercial use, After a few months the wires would get ripped out of them. We have standardized all of our company's (14) trailers to this seven way flat connector. It is the most reliable and secure one I have found.



by:

Great one piece molded trailer wire connector to replace my 2 piece tore up connector. Excellent wiring diagrams available on etrailer.com as well.



by:

Easy to install, I've had it spliced into my boat trailer for a year now and no issues. The body has held up well with no cracks or broken plastic pieces.



by:

Etrailer.com is the greatest online store for all your trailer and vehicle needs.
The item was shipped to my front door quickly and was exactly what I had ordered. I will always shop at etrailer.com whenever parts are needed for my towing needs.
Thank you etrailer.com!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!



by:

The 7-Way molded trailer wire connector arrived in a reasonable time, is of good quality and is much better having the wires molded into the plug for corrosion and security. The only thing I can think of that is lacking is a wiring diagram but the chart on the product description page takes care of that. I will definitely use etrailer again.


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Show More Reviews

See what our Experts say about this Hopkins Trailer Wiring

  • Does Hopkins 7-Way Trailer Connector Have a Wire for Reverse Lights
    Yes, the yellow wire is labeled as auxiliary in the chart on the product page. This wire goes to the center pin which on your Dodge Ram would be the reverse lights. I assume you need this to activate the back-up solenoid for a reverse lock-out so the brakes do not engage when backing up.
    view full answer...
  • How To Wire 7-Way Trailer Connector On Trailer for Factory Plug
    In order to wire up the trailer to hook up to a factory 7-way trailer connector you can simply install a new end, the 7-Way Molded Trailer Wire Connector part # H20042 is what I recommend. I can't tell you what wire colors to hook where as not all trailers are the same but likely the green is right stop/turn, yellow is left stop/turn, brown is running light, white is ground, blue is brake output, black is battery charge, and yellow is reverse. If you don't have all functions you could be...
    view full answer...
  • Replacement 7-Way and Wiring Diagram for Camper
    Sorry to hear about the vandalism of your camper. I attached a couple diagrams for 7-way trailer wiring harnesses. For a replacement 7-way we have the part # H20042 which comes with 3 feet of wire.
    view full answer...
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  • Functions of the White, Blue and Black Wires of the Replacement 7-Way H20042
    The white is ground, the blue is for the brake output circuit for the trailer's brakes and the black is for the auxiliary 12 volt circuit for the trailer. If you have no use for these circuits then they would not have to be connected to anything, you would just need to tie them up and out of the way. I attached a chart that shows the functions of each of the circuit of the connector. I attached an install video for you to check out as well.
    view full answer...
    Image 1 for
  • How To Power Electric Trailer Tongue Jack Through 7-Way
    In order to power an electric trailer tongue jack using the 7-way trailer connector you would simply install a new trailer connector and attach the power wire from the jack to the battery charge line pin inside the trailer connector. If you go with the 7-Way Molded Trailer Wire Connector - 3' Long # H20042 which is what I recommend then just use the black wire. In regard to power a tailgate light bar at the rear of the trailer, you'll need to splice each of the wires into the circuits...
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  • Compatibility of Hopkins 7-way Trailer-Side Connector # H20042 with 2004 GMC Sierra 2500
    The Hopkins 7-Way Molded Trailer Connector you mentioned, part # H20042 is not a vehicle-specific item. It will work well with any vehicle that is equipped with a 7-way trailer connector as long as it is wired correctly. I have linked you to our wiring FAQ article that will run through how a 7-way is wired. Keep in mind that the # H20042 uses a non-typical wire color code, so be sure to wire it by function, not by wire color. The white wire on the connector would ground to the trailer...
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  • Trailer Battery Charge Recommendation for Battery on Trailer that Has 4-Way
    What you will need to do is remove the 4-way of your trailer and replace it with a 7-way like the # H20042 so that you can then run the black wire of the 7-way to the positive post of the battery so that it charges.
    view full answer...
    Image 1 for
  • Installation of Hopkins 7-Way Molded Trailer Wire Connector Based on Wire Function vs. Color
    The 7-Way Molded Trailer Wire Connector - 3' Long # H20042 has different wiring colors than other connectors. The color that will connect to the reverse light function is the yellow wire of this molded connector. They label it Aux as some people choose not to use the reverse light function and add a second 12V power instead. You just want to make sure functions match on either end of the connectors. The Hopkins connectors are different than the standard colors, so you will want to make...
    view full answer...
    Image 1 for
  • 7-Way Replacement Recommendation for Bunkhouse Camper with 6-Way Flat
    We don't have a 6-way flat connector so we don't have a way to create an adapter using one. Only solution we have would be to remove the 6-way flat and install a 7-way flat in it's place like with part # H20042.
    view full answer...
  • Electric Trailer Brakes Grabbing Hard on Trailer
    So there are a couple potential issues here with your trailer's electric brakes that are grabbing hard and releasing on their own. The information about other trailers working fine on the same truck is important because that means we can rule out the issue being on the truck side, and narrow it down to the trailer side. It could always be a bad ground causing an issue with the brake wiring, so start there and see if your brakes have a good ground. The other thing you will want to check...
    view full answer...
  • How To Replace a 5-Way Trailer Connector with 8 Wires Using a 7-Way Trailer Connector
    I am not very familiar with a 5-way trailer connector that has 8 wires like what you have now but it should not be too much work to change this out. I would not be able to give a function for each wire so what you will need to do is apply a 12 volt charge from a battery to see which light illuminates. This will then let you know the functions so you can attach them to the 7-Way Molded Trailer Wire Connector - 3' Long # H20042. The brown wire with yellow stripe likely has the same function...
    view full answer...
    Image 1 for
  • Solution for Installing New 7-Way on Trailer and Not Knowing What Wire Goes Where
    Hey Tim, so in a perfect world all trailers and vehicles would use the same wiring colors for their 7-way connectors and while some do we have found that some just don't at all, or others may use a slightly different color standard. I attached a picture that has the two standard diagrams that by function are exact same but by color are different. You can see which colors you have and match that to the diagram or worse case scenario you could trace the wires to find out the circuit they...
    view full answer...
  • Replacement 7-Way Trailer Connector for a 1970 Airstream Trailer
    Bargman 7-Way Molded Trailer Wire Connector 50-67-210 is an extension that has 2 7-Way connectors, so it is likely not what you need to replace the 7-Way on your 1970 Airstream trailer. For a trailer side 7-Way with a short length of cable you can use # H20042. On it the wires have the following functions: White Wire = Ground Red Wire = Left Turn and Brake Brown Wire = Right Turn and Brake Green Wire = Tail Lights Blue Wire = Brake Power Black Wire = 12 volt (hot lead) Yellow Wire...
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  • Charging a Tolling Motor when Towing a Boat with a 2005 Chevy Silverado
    Given that you currently have a 7-way on your truck, the easiest adjustments to make to your trailer connector would be to change the plug to a 7-way blade, and use the power lead of the new trailer connector to charge your battery. Use half of the wires to splice into the wires on your 4-way, ground the extra wire with the white ground, and run the power lead to the battery you wish to charge. You will need trailer connector part # H20042. If you already have the wiring to complete a...
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  • Trailer Brakes Lock Up When Connected To Trailer Using 6 to 7 Pole Adapter
    The issue you are having with the trailer brakes locking up as soon as the trailer connector is plugged in has to do with the pin out of the trailer side trailer connector in relation to the adapter. The most likely problem is that the battery charge line is crossed with the brake output circuit. In order to fix this you will simply need to just swap out the two wires on the back of the trailer side trailer connector or you can just rewire a new trailer connector on the trailer using the...
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  • How to Determine Functions to Wire New 7-Way to Trailer
    The only way to correctly wire a new 7-way plug and lead like the Hopkins # H20042 is to determine the functions of the wires, and unfortunately there is no kind of universal color code to tell us what wires do what. So you'll need to determine that by using a separate 12 volt battery and using that to test each of the wires on the trailer to find out what their functions are. You will ground the negative terminal and use the battery's positive post for the wires which will tell you their...
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    Image 1 for
  • Wiring In the Hopkins 7-Way Molded Trailer Wire Connector, # H20042
    I will be glad to help you out with wiring up your trailer. To start, I will mention the electric brake wiring. There are 2 wires on the brake assemblies coming from the magnets. One will be ground and should be connected to a bare metal surface on the trailer frame, near the magnet. If the ground is too far away, it may not work properly. The other wire will connect to the blue wire on harness # H20042. This will provide the power to the brakes. The White wire is the ground and it does...
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  • 7-Way Trailer Connector Recommendation for a Boat Trailer with Electric Over Hydraulic Brakes
    Yes, we have exactly what you need. To replace the 5-way you have on your boat trailer with a 7-way you will want the part # H20042. I attached an install and review video for you to check out.
    view full answer...
    Image 1 for
  • Can Fog Lamps Used as Reverse Lights We Wired to 7-way Trailer Connector of 2020 Ram 1500
    If you were wanting to power the fog/reverse lamps using a plug like # H20042, you'd simply attach the ground wire from the lamp to the plug's white wire and the lamp power wire to the yellow wire on the plug. The lamp would power up with the reverse lamps, and none of the other connections on the plug would be needed. If you wanted a cleaner-looking solution that would leave the 7-way at the bumper free and not have the plug powering your fog lamps visible, I'd go with a T-Connector like...
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  • How Would Trailer with 4-Way Wire to the 7-Way part # H20042
    It sounds like your current 4-way has two wires ran to the running light circuit (one for each side of the trailer) and the rest of the wiring is standard. Especially considering the order of the colors that you listed. Green is right turn/stop, yellow is left turn/stop, brown is running light, and white is ground. To wire that to the part # H20042 that you referenced would require you to use the information I just listed and compare that to the diagram picture that I attached. You would...
    view full answer...
    Image 1 for
  • Have Running Lights and Trailer Brakes Function Properly but No Brake Lights or Turn Signals.
    Since all of the functions on the truck are working properly, and you have narrowed down the wiring problem to between the junction box and trailer connector, I believe you have a problem with the trailer side connector itself. Check the inside of the trailer connector for corrosion. If you find green and/or white corrosion that will be where the problem lies. You will need to clean this corrosion out and make sure the connections are secure. Sometimes the corrosion is rather stubborn...
    view full answer...
  • Electric Trailer Brakes Are Not Releasing
    The humming sound you are hearing means that there is 12 volt power getting to the brakes and is normal. However, the brakes not releasing is, of course, irregular and what it means is that the 12 volt circuit and brake controller output circuit of the trailer have shorted together. This is possibly from a short on the trailer itself with an exposed wire, or there could also be corrosion on your trailer's 7-way. If so you can replace it with 7-Way Molded Trailer Wire Connector - 3' Long...
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  • Replacement Trailer Wiring Solution for 1997 Jayco Eagle 10 LD with Square 6-Way
    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 an adapter from Jayco. But to add a 7-Way RV style connector to the trailer you can use something like # H20042. You will need to determine what...
    view full answer...
  • 7-Way Molded Trailer Wiring For Trailer End To Match Up With 7 Blade Adapter On Vehicle
    Some harnesses are different and will not match up correctly with the adapter on your vehicle. I would recommend cutting off the head of the 7 way plug on your trailer and installing The 7-Way Molded Trailer Wire Connector # H20042. This harness is a trailer end connector with a 3 foot lead. I attached a wiring diagram below of which wire goes where and the function of each wiring. I attached an installation video link below.
    view full answer...
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Info for this part was:

Employee Jackie C
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Jackie C
Employee Mike L
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Employee Robert G
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Robert G
Employee Patrick B
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Patrick B
Employee Michael H
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Michael H
Employee Jameson C
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Jameson C
Employee Adam R
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Employee Zack K
Video Edited:
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Employee Cole B
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Employee Alexander C
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