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7-Way Molded Trailer Wire Connector - 3' Long

7-Way Molded Trailer Wire Connector - 3' Long

Item # H20042
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Hopkins Wiring - H20042
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Lowest Prices for the best wiring from Hopkins. 7-Way Molded Trailer Wire Connector - 3' Long part number H20042 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
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Hopkins Wiring - H20042

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


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 Reviews

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

Average Customer Rating:  4.6 out of 5 stars   (148 Customer Reviews)


- H20042
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. 463245



- H20042
by:

Still going strong, no problems and easy to install. 847461



- H20042
by:

perfect 844916



- H20042
by:

Looks great. I was able to find a video on utube about the repair. I also like that there appears to be a way to further secure to mobile home so that it does not fall off again and require another repair. 822008



- H20042
by:

Etrailer always has the hard to find items along with a good selection. I’ve been shopping with them over the years and they are a go to shop. 786361



- H20042
by:

Excellent product. Also etrailer was very helpful when I needed help installing . Great place to do business. 768178



- H20042
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 666842


Comments
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.
-- Mike L - 07/08/2019

57570
Comments
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.
Daniel - 07/07/2020

86302

- H20042
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. 665571



- H20042
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. 657636



- H20042
by:

Looks well made. I have no idea if it is made in USA though. I wish etrailer would give country of origin (when not USA). MAGA! 640697


Comments
Good quality. Easy to work with.
Dennis - 05/11/2020

76205

- H20042
by:

Was just what I needed works well. I stock these now for my customers 577200



- H20042
by:

Great product, excellent company to do business with. 573410



- H20042
by:

product was as described in catalog. completely satisfied. 573254



- H20042
by:

Great products with great customer service. Mailed same day!! 560322



- H20042
by:

Thank you. Used for conversion from hydraulic brakes to electric 548214



- H20042
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. 523714


Comments
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.
-- Rachael H - 06/20/2018

40013

- H20042
by:

thanks for your help 514051



- H20042
by:

Excellent product. Much higher quality than I expected at this price. Online wiring guide is great. Would be good if paper copy accompanied product to avoid mistakes I made first time I connected harness. Excellent quality. 499167



- H20042
by:

Not a problem. Working fine so far. 493000



- H20042
by:

Good service 490796



- H20042
by:

Great product for a great price. Molded plug to repel moisture 482903


Comments
Everything still works great. Thanks.
Jeremiah - 03/09/2019

50333

- H20042
by:

Good replacement for the one that i had that got damaged. 469025



- H20042
by:

Great connector at a great price. 463664


Comments
Product is working fine after a year. Happy New Year.
Calvin R - 12/29/2018

48064

- H20042
by:

The quality of the material and construction appears to be fine. The overall length of the item was short of what was advertised. It'll still work for my project, but I guess it is buyer beware. Wonder if I'd have received the product if I sent less money????? 461252



- H20042
by:

Great part, very fast shipping. Thank y ou. 444616


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Ask the Experts about this Hopkins Wiring

  • Replacement 7-Way RV Harness in Different Lengths
    There are various lengths of 7-way RV harnesses but they have 10 gauge white and black wires for the positive and negative connections. The 7-Way Molded Trailer Wire Connector - 3' Long # H20042 for example uses 10 gauge wires for positive and ground, 12 gauge wire for brake controller, and 14 gauge for the other functions. The Mighty Cord 7-Way RV-Style Trailer Connector w/ Molded Cable - Trailer End - 10' Long # A10-7W10. The same wire gauges line up for the vehicle side like the...
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  • 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.
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  • Tekonsha Prodigy Electronic Brake Cable Replacement for Damaged One Dragging on Road
    Easiest solution we can offer for replacing the 7-way and lead of your Prodigy RF part # 90250 is to hardwire in the part # H20042 in place of the one you lost. Or you could even cut the loom on both side of what you have, strip back the wiring, and then butt end connect all of the connections. For a set of ten butt connectors you'd then want the part # DW05745-10.
    view full answer...
  • Recommended 7- and 4-way Bumper Plug Extension for Use with Cabover Camper
    I have just the thing for you to extend your bumper plug to the end of your camper. If you want to get the 7-way and 4-way you will want the # H20042 and the # HM48470. This combination will need to be wired up but will include the mounting bracket for the 7-way and 4-way. If you prefer to have a prewired 7-way the one you will want it the # TLW6021. All of our prewired ones will only include the 7-way. A mounting bracket for this extension plug is # TM76474. I have linked all...
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  • 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...
  • 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...
  • Recommended Solution for Towing European Trailer with US Vehicle
    The best thing I can recommend you do is you would want a trailer side 7-way like part # H20042 to wire up to an EU socket found local to create an adapter to use your US spec vehicle with EU trailer wiring. I attached a chart that labels the functions of the wires on this connector for you to reference. To gain all the function that a US 7-way carries you will also need to adapt your US 4-way into a 7-way blade to be compatible with the # H20042. For this I recommend the # ETBC7,...
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  • 7-Way Wiring Kit to Upgrade Trailer Wiring on 1999 Viking Pop-Up Camper Trailer
    Since your Viking pop-up camper trailer's wiring is of a different format than the standard 7-way on your 2017 Chevrolet Silverado 1500, which has a 4-pole and a 7-way combination connector, the best long-term solution is to wire in a new 7-way male plug on the trailer using a kit like # e99011. This kit includes the 7-way plug and cable, a wiring junction box and all connectors required to update your trailer to the modern 7-way RV format. The Jayco 6-pole square connector type, which...
    view full answer...
  • 7-Way and Junction Box Recommendation for Wiring Trailer for New Lights
    For all the functions you are looking for you would want to install a 7-way and then use a junction box to organize the wiring. Starting with a trailer side 7-Way connector you can use # H20042 which is 3 feet long. It doesn't have to be long though because it is going to the junction box. Speaking of junction boxes you can use # 38656. I have included a picture showing how it can be wired up and a video showing installation to the right. For the rest of the wiring you can use ...
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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...
    view full answer...
  • 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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  • 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 or 7-way plug like the Bargman # 54-77-003 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...
    view full answer...
  • Wiring Needed to Convert 13-Pin on European Trailer to Standard U.S. 7-Way
    Since there are no adapters to go from a European 13-pin to a standard U.S. 7-way, what you are going to need to do is a bit of wiring. You will first need Converter # C56196 in order to combine the separate brake and tail lights that are on European trailers. After that you are going to need to install a standard U.S. trailer side 7-way, the 7-Way Molded Trailer Wire Connector - 3' Long # H20042 or 6' Long # H20044.
    view full answer...
  • 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...
  • 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...
  • Parts Needed to Re-Wire Boat Trailer to 7-Way Type Trailer Plug
    Yes, you can re-wire your boat trailer that has 4-pole wiring with a 7-way type plug like # H20046. This will allow direct connection to your 7-way-equipped truck without adapters that can cause connection problems in the long run. To install the 7-way plug you will use a wiring junction box # 38656 on the trailer to make the connections between the existing trailer wiring and the new plug. You'll use ring terminals # 44-5310A on both the trailer wiring and plug pigtails to join them...
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  • Parts Needed to Install New 7-Way and Wiring on a Trailer
    Starting with a trailer side 7-Way connector you can use # H20042 which is 3 feet long. It doesn't have to be long though because it is going to the junction box. Speaking of junction boxes you can use # 38656. I have included a picture showing how it can be wired up and a video showing installation to the right. For the rest of the wiring you can use # DW04914-1 which is sold by the foot. So if you needed 20 feet you would enter 20 into the quantity box. And for ring terminals you...
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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...
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  • How to Make a 7-Way to 6-Way Square Jayco Trailer Connector Adapter
    Yes, the Jayco trailers use a very unique wiring on their trailers. There is no adapter available that will go from a 7-Way vehicle side connector to a 6-Way square Jayco connector. You will need to make one using the follow parts: 7-Way trailer connector # H20042 6-Pole Square Trailer Wiring Connector Kit, # 37995 Start by identifying the wire functions of the trailer side connector so that it will be easier to wire in the 7-Way later. Connect the 7-Way wires on H20042 to the...
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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...
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  • How to Complete Electric Brake Wiring to Trailer Connector
    It sounds like you have a junction box like part # 3375601101 installed on your trailer and the brake output wire from the assemblies are ran to this but not to the trailer connector. If that is the case than all you will need is a ring terminal like part # 44-5310A and some spare wire like part # 10-1-1 to finish running the brake output wire from the junction box to the trailer connector. It sound like you may also need a new trailer connector as well and for that I recommend the...
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  • Best Towing Setup for a 2018 Volvo XC90
    For your 2018 Volvo XC90, I recommend using the Draw-Tite Max-Frame Trailer Hitch Receiver part # 76194 because this trailer hitch unlike the Curt Trailer Hitch Receiver part # C13233 will not require any drilling into the frame which is not exactly something most want to do on a brand new vehicle. The install process will be a bit more challenging but the limited vehicle modifications makes it well worth your while. We also have an install video of this hitch which I have attached for...
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  • Electric Trailer Brakes Engaging
    Thanks for the nice words and all that information! It certainly isn't normal that your trailer brakes are engaging without a brake controller though there are a couple of reasons why this can happen. My guess is a wiring issue on the trailer where the wires are making contact and 12 volt power is getting through to the brakes. So I recommend going over the wiring from your brakes and tracing it to see if there is an issue there. If need be you can replace with 10 gauge wire # 10-1-1. Or...
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  • How To Power Third Brake Light On Camper Using Trailer Connector
    If you absolutely do not want to splice into the vehicle you could use the trailer connector to power the third brake light on a truck bed camper but the issue with using the trailer connector is that the stop/turn circuits are combined. Therefore, you would need to make your own adapter using the Pacer Performance 3rd Brake Light Logic Module part # PP20-702 and the 7-Way Molded Trailer Wire Connector part # H20042. If not, the third brake light would also flash with the turn signals but...
    view full answer...
  • 7-Way Blade Replacement for Tow Vehicle and Trailer
    For a 7-way with a wire lead we have the part # 50-87-004 which you could put on your tow vehicle. Then for a 7-way for you to wire to your trailer we have the part # H20042 that also has a plug and wire lead.
    view full answer...
  • Electric Trailer Brakes for a Floe Snowmobile Trailer with 2,200 Pound Axles
    The axle you have that can take brakes probably has a 4-bolt mounting pattern for the brakes. You could use Dexter brakes # 23-48 for the right and # 23-47 for the left. If the mounting flange doesn't take a 4-bolt assembly let me know. In addition to the brakes themselves you will also need wiring, maybe a different trailer connector depending on what the trailer has now (if the trailer has a 7-Way then you would not need to change connectors), and the vehicle will need to have a brake...
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  • 7-Way Trailer Wiring Setup Recommendation for a Tandem Axle Trailer
    A 4-way trailer wiring harness wouldn't carry a brake signal so it wouldn't matter how many axles you would have on a trailer that has a 4-way. A better option would be a 7-way as that style of harness does carry the brake signal. Starting with a trailer side 7-Way connector you can use # H20042 which is 3 feet long. It doesn't have to be long though because it is going to the junction box. Speaking of junction boxes you can use # 38656. I have included a picture showing how it...
    view full answer...

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Info for this part was:

Expert Research:
Jackie C
Expert Research:
Mike L
Expert Research:
Robert G
Expert Research:
Patrick B
Expert Research:
Michael H
Expert Research:
Jameson C
Expert Research:
Adam R
Video Edited:
Zack K
Installed by:
Cole B
Updated by:
Sarah W
Updated by:
Alexander C

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