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.
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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.
Average Customer Rating: 4.8 out of 5 stars (628 Customer Reviews)
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.
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 - 07/25/2019
TomD - 07/24/2020etrailer is a great web-site . Has helped me a lot with trailer brake wiring and brake controller wiring , their products are top notch . Bought the junction box to replace mine as it is an open air terminal strip and gets corroded from the road grime and rain , these boxes are nice for troubleshooting trailer lights with a simple hand held meter and they are weather tight . Have built my own in the past but cant beat this box for price . Have not installed it yet , replacing the trailer floor at the moment and updating the wiring and paint . Excellent product .
Crankshaft J - 02/03/2021Installed 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 - 10/14/2018Every trailer I own has a rat's nest for wiring. This will go on my 16 ft tandem axle to make it easy to straighten it out. I may get a few more of these boxes for my smaller trailers. Make things neat.
I was able to replace a residential electrical box with this Junction Box. The residential box was mass of wires with wire nuts that are not suitable for a 5th wheel trailer. Also, it was almost impossible to track wires when troubleshooting an electrical issue. It is a shame that Forest River would build RVs that could become such a dangerous situation if wires become lose(i.e. Brakes, etc.). Wire Nuts are not to be used in an environment subject to vibrations . I cam now trace my wires with ease, if needed.
Excellent thus far. Installed last spring and went to hook up the trailer after winter and everything still works.
David F - 04/28/2021Rewired 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 - 11/11/2017I 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.
Used a couple of these junction boxes on a complete trailer wiring overhaul. Worked well so far.
Great J - 02/25/2021We wanted both a 7-wire and a 4-wire plug on the same trailer. This junction box made the installation very easy. If your connecting the Hopkins 7-wire harness to this box, you'll probably have to ignore the wire colors names and just use the location (R Turn, etc.). Both are marked on each terminal. There are 5 different openings to choose from to route the wiring to this box and it comes with both rubber grommets to run wiring through and rubber plugs for the openings not used. A downside is that only the side with 2 openings has wire hold downs on the inside. It would have been nice if at least the opening on the opposite end also had such a feature. It's fairly water tight and installed easily onto the frame, under the trailer. Because it's lightweight plastic, I'm not so sure how long it'd last in the direct sunlight if it was mounted on the tongue or other exterior location.
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 - 08/07/2015I 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.
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.
This trailer wiring junction box made rewriting and connecting the harness wiring a snap. Great product!
Bought a 20 year-old horse trailer and needed to rewire it. I used this junction box mounted inside the channel and hooked up the brakes, trailer lights, accessory lights, brake-away switch and battery. Battery and brakes were #10 wire yet there was plenty of room for a neat assembly. This box was well made with sturdy terminals and was weatherproof. I recommend.
Very impressed with etrailer. I've purchased a goosenect connection for my f350 and it has been impressive. I love your products, the way you provide detailed info about each item, videos, photos, dimension, capacities, etc. Way better than anywhere else I've seen. I've found prices to be reasonable. Service has been great with fast delivery. I will definitely continue to shop at etrailer.
Simple design, easy to assemble, some of the wires are a snug fit, but it works. No mounting hardware included. I’d like to see some nuts & bolts and some self tapping screws for mounting. I’m glad I purchased this over butt connecting my trailer wires to my 7-pin connector.
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 wire is very easy to work with and splices nicely. Used in conjunction with a terminal box and a molded 7pin connector lead made my rewire a breeze. Spend a few extra dollars and buy heat shrink or heat shrink connectors and quality cable clamps.
John - 05/18/2020This thing is awesome and should be a must have for everyone who has a boat with electric breaks. Cleaned up my wiring 10X no more blinking lights traveling down the road. Extremely secure connection to trailer, just make sure you get self locking bolts. Also makes grounding to your trailer a none issue and keeps wiring secure and clean traveling down the road. Easy self install too!
This product is very easy to install and seems to be of very good quality. I like the way they designed it so it is waterproof and it came with everything you could possibly need to install it.
Herb B - 05/15/2020Well 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.
This junction box made it very nice to hook up my trailer plug to the trailer wires rather than individually connecting them and trying to keep them sealed from the elements. It also made a much cleaner set up. The box itself is made of a rigid but flexible plastic rather than a hard plastic that tends to break.
Charlie - 07/03/2019worked great, wired it up to be used with my 2 wheel dolly for camping trip to Grand Teton National Park and back to Washington State
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