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40 Ft 5-Way Trailer Wiring Harness - Wishbone Style - 30" Ground - 5' Auxiliary Wire

40 Ft 5-Way Trailer Wiring Harness - Wishbone Style - 30" Ground - 5' Auxiliary Wire

Item # A40W5B
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Optronics 5 Flat Wiring - A40W5B
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5-Way trailer harness connects to your tow vehicle to control trailer light functions. Wishbone-style harness comes with 2 tail light wires split for simple wiring. Auxiliary wire signals trailer brakes to disengage when in reverse. Lowest Prices for the best wiring from Optronics. 40 Ft 5-Way Trailer Wiring Harness - Wishbone Style - 30" Ground - 5' Auxiliary Wire part number A40W5B can be ordered online at etrailer.com or call 800-298-1624 for expert service.
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Optronics Wiring - A40W5B

  • Trailer Connectors
  • Trailer End Connector
  • 5 Flat
  • Plug and Lead
  • 31 Feet and Longer
  • Optronics

5-Way trailer harness connects to your tow vehicle to control trailer light functions. Wishbone-style harness comes with 2 tail light wires split for simple wiring. Auxiliary wire signals trailer brakes to disengage when in reverse.


Features:

  • 5-Way trailer harness connects to your tow vehicle to control trailer light functions
    • Ideal for marine trailers with hydraulic or surge brakes
  • Wishbone-style harness comes with 2 tail light wires split for simple wiring
    • Allows you to run wires separately down each side of the trailer to tail lights without needing a jumper wire
  • Auxiliary wire (blue) connects to backup light circuit to disengage surge brakes when you are driving in reverse
    • Hydraulic actuator must have electric lockout feature built-in to disengage the trailer brakes
  • Color coded wires help with installation
    • White - ground
    • Brown - tail lights
    • Yellow - driver side stop/turn
    • Green - passenger side stop/turn
    • Blue - auxiliary wire


Specs:

  • Wire harness length: 40'
  • Ground wire length: 30"
  • Auxiliary wire length: 5'


Manufacturer Cross Reference
Harness will work as an exact replacement for:

  • Truck Lite # 002295


A40W5B Optronics 40 ft. Wishbone 5-Way Trailer Harness with 30" Ground and 5 ft. Blue Wire

Alternate part number: A-40W5B




California residents: click here



Customer Reviews

40 Ft 5-Way Trailer Wiring Harness - Wishbone Style - 30" Ground - 5' Auxiliary Wire - A40W5B

Average Customer Rating:  4.9 out of 5 stars   (90 Customer Reviews)

5-Way trailer harness connects to your tow vehicle to control trailer light functions. Wishbone-style harness comes with 2 tail light wires split for simple wiring. Auxiliary wire signals trailer brakes to disengage when in reverse.

- A40W5B
by:

Completely rewired my trailer and this kit had all that I needed.



- A40W5B
by:

THE PRODUCT CAME QUICK AND ETRAIER AS THE ONLY PLACE TO HAVE THIS PRODUCT. 40 FT TRAILER HARNESS . WE WILL BE INSTALLING IT ON MY 2010 CONTINENTAL BOAT TRAILER . FILMING IT ON MY YOUTUBE CHANNEL . .SHALLOWHOOKERFISHING.COM . ILL BE HAPPY TO MENTION ETRAILERS.COM ON MY CHANNEL. .



- A40W5B
by:

Good product Easily required my boat tr ailer



- A40W5B
by:

Item seems to be high quality was installed last night and worked as it should.



- A40W5B
by:

product was I expected and good quality, shipping seem slow



- A40W5B
by:

I got my 40ft wishbone trailer harness in about 5 days. Was held up a day because of the Christmas holiday. All in all I was quite satisfied with my purchase. I'm putting "Pole Lights" on my trailer to keep them out of the water. I didn't want to "splice any wires", so I ordered the 40ft length. I have not yet installed this, but plan to start today. Its been a very busy holiday season, and now time to get to work. Capt. Jim Hedgecock



- A40W5B
by:

Last Fall I ran new trailer wiring for my boat trailer. This wiring was great for the application and trailer lights work great today.



- A40W5B
by:

Got the job done.



- A40W5B
by:

Design wise it is excellent, the wishbone design is intelligent and makes rewiring a boat trailer simple and clean. The Good rating? The wire gauge looks to be 18-20, wish it was heavier gauge, especially since it is a 40 ft long harness. And it is made in China or Taiwan, not a heavy duty or perfect construction. If it lasts as long as my original, 14-years, I'll come back and bump up my rating, and I bet you can't find a better one. As far as the transaction, it was excellent, had the 40 footer I needed, great price and super fast shipping.



- A40W5B
by:

Very pleased with my 40’ 5 pin trailer harness. Highly recommend these guys!



- A40W5B
by:

Replaced old corroded wiring . was just what I needed , all lights work perfectly now



- A40W5B
by:

Good product. Length was perfect.



- A40W5B
by:

Very satisfied with product. Only recommendation is charge an extra minimal amount for splices, terminals and etc. In my DIY application, replacing the bumper plug connector. I'll retain the remaining wiring harness for near future replacement.



- A40W5B
by:

Doesn't get any easier! Product described well. Easy navigation on order page, checkout and product arrived in a reasonable time. Will install the harness this weekend..



- A40W5B
by:

Perfect for what I need for the Pontoon Trailer.. Plenty wire length



- A40W5B
by:

The product quality was very good. We were happy to find everything we needed to restore our boat trailer in one place.



- A40W5B
by:

came fast. good product


Comments
EXCELLENT, WORKING WELL
Paul D - 07/29/2020


- A40W5B
by:

This product made it simple to re-wire my boat trailer, and was delivered as promised. Excellent customer service was given to change my order after I had discovered I had originally ordered the wrong part.



- A40W5B
by:

Excellemt product and service as always. Etrailer is the best source for your products . They have outstanding service and pricing.



- A40W5B
by:

Just what I was looking for. I believe this is going to work as I run the wire from the front of my 5th Wheel to the back.


Comments
It is working out fine. Thanks Etrailer.
John B - 12/09/2014


- A40W5B
by:

Another great product with super service from etrailer.



- A40W5B
by:

Etrailer is awesome Great website for detailed parts I buy from etrailer all the time


Comments
Great etrailer is awesome
Jim m - 05/10/2018



- A40W5B
by:

Great communication It took a little longer to deliver But great service and great products



- A40W5B
by:

etrailer is a the only place I could find this item as I live in a rural area. The harness was perfect and did the job well. Service and shipping time was perfect.



- A40W5B
by:

Product was shipped quickly and matched the product description. Tried to find it locally for a price comparison but nobody stocked this item. Shopped online and etrailer.com had the best price. Good product, good service. Thank you.


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Ask the Experts about this Optronics Wiring

  • Replacement 5-Way Trailer Wiring for Boat Trailer
    For new 5-way wiring what you'll need is the part # A40W5B. This will handle all of the wiring that runs from the connector back to the lighting assemblies as well as for a reverse lock out solenoid. Surge brakes don't always require wiring as they don't always have reverse lock out solenoids. It's very possible yours does not have one so wiring may not be needed. If you see a solenoid at the back of the actuator on the brake line you will want to run the blue wire of the 5-way to it. I...
    view full answer...
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  • Wire Gauge Size of the 40 Ft 5-Way Trailer Wiring Harness A40W5B
    The 40 Ft 5-Way Trailer Wiring Harness part # A40W5B uses 20 gauge wire according to Optronics. This is pretty standard and will work for the vast majority of trailers without issue.The Wesbar 5-Pole Flat Connector part # W002290 uses larger 16 gauge wire if that is what you are looking for.
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  • Parts Needed To Rewire Trailer Using 5-Way for Reverse Circuit
    I have just what you need to rewire a trailer using lights with a built-in reverse function. For this, I recommend a standard 5-way trailer connector which will provide circuits for stop, turn, tail, and reverse. The 5-Way Trailer Wiring Harness part # A40W5B is what I recommend for this as it has enough wire to completely redo the trailer lights with all new wires. I also recommend the Deka Heat Shrink Butt Connectors part # DW05744-10 and CE Smith Trailer Wiring Clips part # CE16867A...
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  • What is Thickest Gauge 5-Way Trailer Wiring Harness
    The 5-way harness we have that has the thickest gauge wire is the Hopkins # HM47910 which has 16 gauge wire. The # A40W5B you referenced uses 20 gauge wire and the other part number you mentioned is a lighting kit and not a 5-way.
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  • Replacing 5-Way on Trailer that Used 8 Wires
    The # A40W5B would be a really great choice although it only has 5 wires ran to it. You'd just need to combine all of the similar wire colors to the single circuit of the new 5-way. The brown and brown/green would go to just the brown of the new 5-way.
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  • How To Re-Wire Your Boat Trailer's 5 Way Wiring And Install New LED Lights
    I recommend using 40 Ft 5-Way Trailer Wiring Harness # A40W5B, which is a kit that will replace your entire 5 way boat wiring setup and give you the 5 way connection at the front of the trailer. The lighting wires are 40 feet long, which will be more than enough. It comes with a 30" ground wire (white) that will be connected to the frame of your trailer. The blue wire is 60" and will be connected to your brake solenoid if you have one; your trailer may not require this, as it may use a...
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  • What are the Functions of a 4-Way Flat Trailer Wiring Connector with 5 Wires
    What you are describing is called a wishbone harness. This is different than a 5-Way flat connector like # A40W5B that you have referenced. A wishbone harness will have 5 wires, 2 of them going to the running light pin which is right next to the ground pin. This is so you do not have to splice in a jumper wire to go from one tail light to the other for the running light function. A 5-Way flat will have 5 wires (though there are also wishbone 5-Ways) and the extra pin is usually attached...
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  • Where Does Blue Wire of Trailer Wiring 5-Way Normally Run to on Trailer
    So the blue wire of the 5-ways like the # A40W5B normally runs to the reverse lockout solenoid of a surge brake actuator like what you described having. The blue wire on the vehicle side of the wiring runs to the reverse light circuit. This allows the solenoid to have voltage when the vehicle is put in reverse preventing the brakes from applying. This runs right to the back of the actuator on the trailer coupler which is why you don't see the wiring ran to the back of the trailer.
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  • Wiring a 5 Flat That Has 8 Wires
    There is not going to be a 5 flat that has 8 wires; the functions of the 8 wires are likely ground, running light circuit (split into 2 wires at the plug), left turn, right turn, brake lights (possibly split at the plug), and output to reverse lockout. What you will need to do is use a circuit tester such as # 40376 to determine the functions of the wires and wire them to 5 flat # A40W5B in the traditional manner of a 5-way which is ground, running lights, left turn/brake, right turn/brake...
    view full answer...
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  • 4-Way Trailer Wiring Recommendation for a Utility Trailer
    A 5-way is usually seen on trailers that have either reverse lights or a reverse lockout for a surge brake system. If you have no need for a 5-way you could use a 4-way like the part # W787268. If you did want to install a 5-way you would want the part # A40W5B. A 4-way connector on a tow vehicle would still plug into a 5-way on a trailer. The fifth circuit just wouldn't be active. To make the install simpler and cleaner a junction box like part # 38656 would be a great option. Check...
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  • 8 Wire Boat Trailer Wiring to 5-Way Plug on Truck
    There is not going to be a 5 flat that has 8 wires; the functions of the 8 wires are likely ground, running light circuit (split into 2 wires at the plug), left turn, right turn, brake lights (possibly split at the plug), and output to reverse lockout. What you will need to do is use a circuit tester such as # 40376 to determine the functions of the wires and wire them to 5 flat # A40W5B in the traditional manner of a 5-way which is ground, running lights, left turn/brake, right turn/brake...
    view full answer...
  • Adding a 7-Way Trailer Connector to a 28 Foot Trailer with Electric Brakes
    The 5th function for 40 ft. Wishbone 5-Way Trailer Harness with 30" Ground and 5 ft. Blue Wire Item # A40W5B is meant to go into an electric reverse lockout on a trailer with surge brakes. On the vehicle side the 5th function ties into the reverse lights so that when the vehicle is in reverse the lockout solenoid will be energized and not allow brake fluid to actuate the brakes. Usually on a trailer with electric brakes both the trailer and the vehicle will have a 7-Way trailer connector....
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  • Replacing 5-Way Trailer Harness That Has 7 Wires
    When a 4-Way or 5-Way pin wiring harness for a trailer has more wires than pins, like the Optronics # A40W5B, it just means that the manufacturer is trying to make it easier on the installer. In your case it sounds like your trailer has 2 ground wires and 2 running light wires that run down either side of the trailer. If this is the case then all you have to do is splice the browns together and the whites together with your new harness and everything should work great! I have attached...
    view full answer...
  • Need Wiring and 5 Way Connector for 26 FT Boat Trailer with Surge Brakes
    When it comes to replacing the wiring on your boat trailer with surge brakes, I recommend using our 40 FT Wishbone 5-Way Trailer Harness with 30" Ground and 5 ft. Blue Wire, # A40W5B. I have included a short video for you. If by chance your tow vehicle is equipped with a 7-way connector, now would be a great time to make the change on the trailer. Should you ever find the need to tow the boat with another vehicle, the 7-way connector is much more universal connector and no adapter would...
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  • Determining Wiring Functions On Trailer To Install New 4-way Connector
    Typically there is a white, green, brown, Yellow/Green and brown, and a yellow wire so since you do not have a dedicated yellow wire you will need to test wire functions by using connecting the brown, green, yellow/brown, and green brown one at a time to the positive terminal of a battery while grounding the white wire and seeing which functions come on with each wire. Since the colors on your old connector are not standard you will need to make the connections by function and not the color...
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  • Wiring Guide for Installing Lights on Trailer with 5 Wires
    A trailer can have either 4-pole or 5-pole connectors and the number of actual wires can vary too. For instance, the part you referenced # 16-4B-1, is 4-pole wiring like what is included in a part like # W787274 which is a trailer-side 4-pole setup that carries stop, turn and tail light signals. There are also 5-pole connectors like # HM47910 that add one additional circuit that can be used for trailer brakes or another function. Then there are also wishbone style harnesses that have...
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  • Recommended Trailer Wiring to Add Reverse Lights to Boat Trailer
    The Fusion LED Trailer Tail Light - Stop, Tail, Turn, Backup - Submersible - Oval - Red/Clear Lens # STL211RB is a great light. You will need to rewire your trailer and then use a converter for your 7-way plug on your F-350. I recommend using the 40 Ft 5-Way Trailer Wiring Harness - Wishbone Style - 30" Ground - 5' Auxiliary Wire # A40W5B to allow you that reverse light function and then use the 7-Way to 5-Way/4-Way Trailer Adapter for Vehicles with Lamp-Out Sensors Towing Trailers with...
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  • Recommended 5-way Connector To Replace Damaged 5-way Connector With Two White Wires
    I have an option for you, but we do not carry a 5-way connector that has two white wires. What I recommend is the # A40W5B which has the two brown running light wires, one green passenger turn signal and brake wire, one yellow driver side turn signal and brake wire, and a blue wire which is commonly used for a reverse lockout solenoid. You will need to cut the connector off the # A40W5B as far back as needed and match the colors. Since you have two ground wires you will need to cut...
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    For your wiring, you will need to test your wire functions to know which one connects where. I recommend using a 12v battery and simply connecting the negative terminal to the trailer frame and then connecting the power to each wire at the connector individually to determine function. It is not uncommon to have two wires running to one function location for each side of the trailer so there aren't any jumper wires across the frame needed from side to side. I've attached an article...
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  • Recommended Trailer WIring for 4-Way Flat, 5-Way Flat, 6-Way Round, and 7-Way
    For a Trailer Wire Harness I recommend the following options: For a 4-way Trailer Harness use # A35W42B. This is a wishbone harness so it has wiring to each side of the trailer separately. Likewise for a 5-way wiring harness use # A40W5B. For a 6-way, I recommend using a junction box like # 38656 with Connector and Lead Wire # H20036 For a 7-way, I recommend # e99011. The remaining wires will use # 12-2-1 or # 12-1-1 sold by the foot. I've attached an article to assist.
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  • Replacement Trailer Side Wiring Harness for a 1996 Yacht Club PWC Trailer
    Trailer side wiring harnesses are not specific to the trailer so you can use any one that has the proper connector and length for your 1996 Yacht Club PWC trailer. I have included a link to the trailer side harnesses for you. If your trailer has a 4-Way flat connector a popular option is wishbone harness # A35W42B. A wishbone harness has 2 wires connected to the running light pin so you won't have to run jumper wires from one side of the trailer to the other for running lights. If...
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  • What are the Functions of a 5-Way Flat Trailer Connector with 8 Wires
    On a 5-Way trailer connector, usually found on boat trailers, the pin on the end furthest from the ground pin is used on an electric reverse lockout on the trailer coupler. This is so when you put the vehicle in reverse, it will single a solenoid on the coupler and not allow fluid to go back to the brakes so you can back up without the brakes engaging. If this is what is on your trailer then you would not want to switch to a 4-Way connector unless you also switched to free-backing brakes. It...
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  • Available 5-Flat Wishbone-Type Trailer Connectors
    We do not carry (and I have not seen) a 5-flat type trailer connector with the many multiple wires for each pin that you describe. We DO have wishbone 5-flat connectors like # A40W5B and # W002290 which have two brown running light wires to simplify connection to the tail lights on both sides of a trailer. What you describe sounds like a custom-made part. I can understand the three white (ground) wires especially if the trailer were made of aluminum which makes establishing multiple...
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  • Troubleshooting Trailer Wiring with Brittle Ground Wire That Keeps Breaking
    If the wire is that fragile, I recommend replacing it now. If you can find a part of the wire to splice into then you can absolutely do that, but if it is too fragile then it won't provide a good ground and the other wires in that harness are likely made of the same material. If you can find a solid point of the wiring you can splice in # 16-1-1 with butt connector # 05731-5 and ring terminal # DW05737-1. I recommend the 35 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 42" Ground...
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  • Recommended Wishbone Wiring Harness to Rewire Trailer with Surge Brakes
    Rewiring your trailer is something that you can absolutely do easily and there are harnesses called wishbone harnesses that don't require any wiring across the trailer frame. I recommend the 35 ft. Wishbone 4-Way Trailer Wiring Harness with 42" Ground Wire # A35W42B. I've attached a review video as well as an installation video to assist. I've also attached an article on wiring to assist with diagrams. If you have the electric reverse lockout on your trailer coupler, you may want the...
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  • Wishbone Trailer Wiring Harness for a Magic Tilt Boat Trailer
    I believe you have what is referred to as a wishbone wiring harness. A wishbone wiring harness has 6 wires and is the same as a 4-way for the exception that it has both running light wires ran to the trailer connectors as opposed to splicing them together and then running them to the trailer connector. The functions should be as follows: Green - Right Turn/Brake Yellow - Left Turn/Brake Yellow/Brown - Left Running Light Green/Brown - Right Running Light White - Ground Red - Reverse...
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  • What Pin on the Hopkins Endurance 4-Way Flat Trailer Connector Is For Side Marker Lights
    If you take a look at the attached photo of the Hopkins Endurance 4-Way Flat Trailer Connector part # HM48110, you will see a two letter code for each terminal. The correct terminal for the clearance/side marker lights is shown as "TM" which is a black/brown wire. In regards to wire gauge, you will not have any issues using a 16 gauge wire from the lights to the 18 gauge wire on the trailer connector. The Fusion LED Trailer Tail Light - Stop, Tail, Turn, Backup part # STL211RB that you...
    view full answer...
    Image 1 for
  • Wiring Needed to Rewire a Trailer for Lights and Electric Brakes
    Both the # A40W5B and # W002290 have a blue wire that is only 5 feet long. Plus, the blue wire is only 18 gauge and 20 gauge, respectively. So these are not going to work for your application. What you're going to want to use is Bonded 4 Wire # 16-4B-1 which is sold by the foot. This will provide the four 16 gauge wires to run from the junction box, part # 277-000141, to your trailer's lights. Then for the brakes you will want a 10 gauge wire, # 10-1-1, which is also sold by the...
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  • Wiring 5-Flat Connectors on Jeep and Trailer
    It sounds like your trailer has a 4-flat wishbone connector, which will have 5 wires with two of them going to the tail light wires. If your trailer has brakes you will need to wire a 5-flat # HM37908 on your Jeep. For this harness, the white wire is the ground wire, the yellow is left turn/brake light, the green is right turn/brake light, the brown is tail lights and the blue is reverse lights. Your trailer will also need a 5-flat # A40W5B, which has a blue wire which disengages the...
    view full answer...

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Info for this part was:

Employee Michael H
Expert Research:
Michael H
Employee Jameson C
Expert Research:
Jameson C
Employee Brian T
Updated by:
Brian T

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