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This Spectro trailer wiring junction box provides a fast, easy way to connect the wires from the trailer connector to the wiring for either a 6-way or 7-way connector. Makes replacing your trailer's connector simple.
Features:
Specs:
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Today were going to install part number 38656. This is a trailer wiring junction box. First thing were going to do is find the location for our junction box. Were going to go ahead and install on the inside edge of the tongue. Well go ahead and hold it up to the tongue and then well go ahead and use a drill to mark it for our holes. We have our holes marked, well go ahead and remove the box, and then go ahead and drill out our hole.
Now well go ahead install our hardware and install our box. Now were going to use a quarter inch hardware to install the box to the frame. This hardware does not come with the box. With our box installed, we can go ahead and start getting our wiring ready. Well go ahead and cut our wires to the length of what we need and then well take our excessive length from our gray cable and use the white wire for our ground lead.
Were going to take the white wire, well add a couple of ring terminals, and well go ahead and connect it to the post labeled white and ground. Well also change out one of solid grommets for a hollow ground. With our new grommet installed, well go ahead and fish our wire through, and attach it to the box, and then were going to use a self-tapping screw to attach it to the frame. Now well go ahead and get the rest of our break cable ready, the gray cable will be for our electric brakes. Well cut back the gray sheath to expose our two wires.
Our white wire will go to ground, our black wire well go ahead and post to label blue, blue is only the function for brakes. Well go ahead add some ring terminals to it, then temporally put them into position. Now well go ahead and hook up our wires for our trailer lighting, well also go ahead and run it through the grommet and then go ahead and install our ring terminals. Now the brown wire on our trailer will be even running light circuit that will go to the post labeled brown, it will also say taillights on there. The green wire will be our right turn signal, well go ahead and connect that wire to a post labeled green, and it will say right turn.
The yellow wire well be our left turn signal and that will be connected to post labeled yellow and left turn. Now these wires have been loosely installed. Next well go ahead and wire our trailer connector, this is going to be a seven molded trailer wire connector, eight foot long, part number h20046. You see the seven pole and we have our wires. Once thing to know about this is that the functions do not match the colors better on the trailer. Now on the other side of the box well go ahead and replace them with solid grommets with a hollow grommet and well go ahead and run that over our wire that we can go ahead and push the wire back into the box. Then well go ahead and add our ring terminals to our wires. Now well go ahead and start attaching our wires, well start off with the green wire from the seven-pole which will be our running lights; this will be connected to the post with the brown wire from the trailer lights. The brown wire will be our right turn so that it will be connected to the post with the green wire from the trailer lights. The red wire will be the left turn function on the seven-pole, so well connect that to the post with the yellow wire from the trailer lights. Our blue wire will be our brake control power, so well hook that up to the post labeled blue. Now our yellow wire is usually reserved for reverse light or whatever function youd like. However, this application is not being used, so well just ignore that wire. Our black wire will be our 12 volt power supply, however this trailer is not using it right now, but well keep it to the junction box for our upgrade in the future. Well now go ahead and take our white wire push it to the ground from our towing vehicle that will be transferred to the trailer and well connect that back up to the white post, well get two white wires. With all of the wires in place well go ahead and tighten down the nuts. Next well go ahead and install the clamp from the wires that come in from the trailer side. Looking at the box on the left hand side there is provision for a clamp. Well make sure everything is pushed together properly and wont get pinched, well go ahead and install the cover. Well fasten and replace of these two bolts. Thats what it takes to install our junction box. All right with that it will finish it for our install of part number 38656, a trailer line junction box on this new trailer.
Customer Satisfaction Score:
100% were satisfied with this product
0% of customers were not satisfied
Ratings & Reviews
Just what I needed!
Well made product with a great design. The only criticism I have of the product is the cheap flat head screws provided with it. They should be stainless and the smaller ones Phillips head. If the screws were of be it would have gotten a five star rating.
It was nice for organizing the wires and install. The rubber wire hole plugs are not the best. One month outside in the sun and the top one dried out and cracked. I guess install it some where it is protected from the weather.
Just what I need to easily wire up my snowmobile trailer, was tired of corroded wires, great product!
This junction box was exactly what I needed. Had a short from cable wear and needed to splice on a new pigtail. This box made it super easy and really clean.
Installed this Junction Box while repairing some previously installed sketchy wiring. Having access to these wires made a ground issue we were having very easy to diagnose. Very good product.
ordered junction box after I got the 7 pin pig tail and I got it installed , everything looks and works great. Thank You
It is going to serve the intended purpose of gathering all these wires into a controlled location. The only drawback is the labelling on the box for the wire locations is extremely difficult to read. Not a big deal.
Thanks for your help with parts for my trailer build. My wife and I are still making custom cabinets out of curly maple. We hope to finish this winter. We have taken it out 7 times this season. Thanks again.
Wiring junction box; made wiring easy; must have item.
Installed as I had planned and it went well. Wired the supply line to the box to all of the correct wiring terminals as it is labeled in the box. I was prepared by other reviews, things may not match up, which they didn't, but no biggie. Once I flipped a few wires around things worked nicely.
Now I have a chuckwagon that is all tricked out for side marker lights and more. This box really did the trick for keeping wires organized.
Junction box was great had it installed and wires hooked up in a little over an hour. Service and shipment was better than expected. Will definitely use etrailer for more of my needs, very good company. The only thing that took a while was the molded seven connector wire colors don't all follow standards, but a test light and a few minutes and it was figured out.
I love these boxes. I've repaired numerous trailers my sons and I own, including cargos, flat beds and horse trailers. I really like the grommet locations, cable clamping and posts for wire connections. There is plenty of room inside to neatly route wires.
Just what I need for my 91 pickup rebuild and update!
Thank you, you always have the right product for my multiple projects.
Had some real issues with this one. Should have noticed when purchasing this harnes is not wired using standard truck/trailer color format. Other than that it went together fairly nice. If the connector would come apart I was thinking of fixing the wiring my self.
This trailer was built from scratch using only the metal frame. I purchased some items from etrailer an was very satisfied with the products.
Wayne M.
8/7/2015
Its still working great.
I purchased this product after researching current trailer rewiring methods. I recently had my entire 18' trailer wired and upgraded. The trailer is 8 years old and I wanted to replace the original 4 way trailer harness which the trailer manufacture had surrounded in electrical tape which also needed an adapter. After some research, I opted for this 7 way pigtail (50-67-005) which is the connector I needed my trucks and this junction box. (all contacts were current)
The junction box is sturdy and well made, we installed 7 way wire within the box with a snug fit. The trailer now has a clean professional appearance and most test functions can be performed from the junction box location. The junction box was installed behind the trailer tongue frame to minimize the weather elements. This product appears to seal well as the product description indicates. I am very satisfied with this product and Etrailer's customer service.
I mounted mine onto a piece of aluminum flat stock on the trailer “A” frame to reduce rock impact from Nevada’s gravel back roads. There really wasn’t good location on inside of trailer frame rails, was adding electric brakes and converting from 4 pin to seven. . I’m pretty darn happy with this junction box as it made rewiring rather straight forward. Our local 12 volt guru at the auto electric shop was duly impressed-wanted to know where I found it.
The product and services are great. I will buy from etrailer again. But the shipping experience through USPS was poor. I would recommend reconsidering them as a logistics service.
I needed a way to reorganize wiring for my very old utility trailer. This wiring junction box from etrailer met my needs exactly and made my re-wiring project easy
Dale P.
7/14/2022
It works well to organize wiring.
Rewired my trailer and used this junction box to go from my main cable to all the individual lights and brakes. It worked great, the only thing I didn't like about it was that it only had two cable clamps on the inside
Chris B.
11/11/2017
I still have all the electric supplies from etrailer on my cargo trailer. I have had no issues with any of your products whatsoever. I hope this helps
Installed in about 30 minutes, made install a breeze and took the mess out of a rats nest of wiring spliced under the trailer. Comes with plenty of grommets and all hardware to put together. You need to supply the bolts or screws to mount this to your trailer. Each terminal is labeled for what connects to it taking the guess work out of matching wires up.
Richard P.
10/14/2018
Still works great, no issues at all.
This box was used as part of an electric brake conversion on my trailer. This box was an excellent means of connecting the existing wiring and the new brake wiring into the new 7 way trailer connector. It has the required breakouts and grommets needed to make the wiring task the easiest part of the conversion.
Mike L.
7/25/2019
For a neat install and ease of replacement later if necessary, theres no better way to go than a junction box.
Tomd
7/24/2020
Im very satisfied with this connection box. It keeps all of the connections well insulated and out of the weather.
Considering the price point this product is well worth it. Having a junction box on the older camp trailer is far better and safer than the wire nuts and crimped wiring that it had.
Mark
11/2/2025
After a full year and over 12,000 miles, this product has performed flawlessly.
Gwendolyn Y.
11/3/2025
Gwendolyn Y.
11/4/2025
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Mike D.
3/26/2015
Great job! Looks like a high quality build.