I got my new trailer and the wiring is downright scary. I think I might be most comfortable just re-doing the entire thing.

The trailer has 5 sidemarkers on each side, spot lights, rear stop/tail/turn, rear clearance lights, license plate, electric brakes, etc.

What is this best way to do this?

I see tjtrailers.com has stuff like this:


About $1/foot.

Would wire like this need to be covered with split loom?

And what is the best way to split off of wire like this to hook up the connectors for lights as I go along... or is there something better to use?

I will be 100% LED except my spot lights... and except my brakes which pull 13 amps. What gauge wiring should I have on 50 feet of wiring (that is 50 feet behind my trailer hook up on my truck....)

 

Sounds like the project i did about two years ago on my old horse trailer. I got nearly all of my wire (6 way and regular for connecting), lamps, etc from https://www.delcity.net/. They worked out great for me and much cheaper than many other places i have seen. I had to buy a 100ft roll of the 6wy/14ga--that way I would have some left to do my other trailer (hasn’t happened yet)

I soldered and heat shrank all of my connections--it took a lot more time, but i think it will be worth it in the long run. I ran the 6 way wire to the very back. I tapped into the wire in the gooseneck area and ran a separate wire for my roof clearance lights (16 of them!) I connected the brakes and tail lamps (4 of them) directly to the 6way wire. I also grounded the trailer in the gooseneck and the rear. Good trailer ground is very important.

As far as the wire size needed, there are numerous electrical websites that will tell you correct gauge for length and amps. I like to have 14ga for brakes, though it’s probably overkill for marker lamps. Its also important to remember the wire size of the attachment; my marker lamps were like 18 or 20ga and it was difficult to connect them to the 14ga at times. 12 ga may be difficult to work with.

I wish my very tight budget would have let me do LCD's. Good luck. Have lots of patience when soldering all of those connections!

 

I would recommend 2 diff harnesses.

Reason being, if you ever tow this trailer, or use the truck, to tow something else.

One harness for the standard stuff, and the other for the extra stuff.


I am fixin to have to do this on mine, as my gn wiring and truck work fine, but they dont work with my dad's boat, or with my friends car trailer.

The in bed connections for my GN works great, but if I hook to the factory one, my traielr b/u lights are on all the time, and I haven't checked to see if the trailer brakes will work using the factory conn yet either.

it would be easier to have one basic harness, and one for the extra stuff. that way, if the trailer is a basic hook up, you won't have issues with things not working, or working all the time like I now have.

 

Patrick Campbell, the 127c500 will work. Suggest using aluminum, rubber coated loom clamps. Soldering & heat shrink is the way to go. Good luck and post some pics when your done.

 

Nice site - Thanks. Definitely cheaper than tjtrailer.com.

What is the best way to do this in terms of how to run the wire...

If I have the one large 6 or 7 way wire go down 1 side of the trailer, I still need to hook up the clearance lights on the other side...

 

I ran a single seperate wire along the top of the trailer, i attached the front clearence lights and then made my way along the side of the trailer to the rear. Each of the front/rear clearence lights were connected directly to the roof wire. The side marke lamps on the one side were connected directly to the wire and the other side had "extensions" running accross the top of the trailer to the primary roof wire. The less joints in the wire you have = the less room for problems later.


TCM- the wiring problems you have in matching up with other trucks is likely a result of the trailer plug--usually very easy to rewire to match universal codes to eliminate your mismatching problems with other trucks.

 

If you are serious about rewiring your trailer to eliminate headaches and ease of maintenance start with 7 wire commercial trailer cord (I prefer ArcticFlex) you will need 3 terminal boxes and some 2 wire cased commercial wire. #1 terminal box goes at the front of the trailer where the truck cord connects and the front markers and top lights if you have them. 2nd box goes between the axles on the frame to supply the brakes and center markers. 3rd box iis at the rear for the major rear light junction and possible extra plug in for 2nd trailer or extension lighting. I no longer use solder as it is slow and makes the wire brittle at the joint, instead I buy the non-insulated butt connectors and use only double wall shrink tube. This produces a joint as strong as soldering but is easier and faster to assemble, single wall shrink tube was designed for wire coding and insulating. Double wall has glue which when warmed up and shrinks squeezes into the joint and spaces it covers with a true seal. LED's do not need the wire size that regular bulbs or brakes do but trailer wire has the right size ground which is more important. I use the 2 wire cased cable for chafing and strength as well it puts a postive ground to every light, brake and the plug- frme grounds and screws are to succeptable to corrosion. I use Trucklite light units (LED or sealed beam) because of quality and warranty. Terminal boxes (prefer rectangular) all have the studs color coded so the wiring is consistant through the entire trailer. This method does cost more but I would rather spend the time and money at home the first time instead of on the road in the rain, snow, mut etc. To plug into the truck my trailers now have an RV sealed plug and coiled cord made by Bobtail products$$ but well worth it. Properly grounded brakes (no frame ground) will work better consistantly. The wire looms discussed (rubber covered) are premium and the right size holds the cable really well. All this is worth it when you don't have to field repair or when you sell the trailer it brings more. PK

 

Sounds good. I will admit I am a user of butt connectors. I will solder when I have to but when I have plenty of wire to work with...I like the ones that have the heat shrink around them already.

Where should the brakes be grounded. My 7 pin receptacle on my truck is grounded to a bolt on my truck frame where the paint is stripped away but I can easily change this.

I was planning on using one of these:

 

I know, but what I was getting at, was ALL trailers use brake, park, signal lights. not all have a winch, b/u lights, trailer brakes, etc.

In the connector shown 4 of the 6 flat pins will be used by right/left turn, park, and brake. Add another one for trailer brakes, and 1 for B/U lights (Like I have). You have now used all the flat pins, and only have the center pin left. If there is anything else that needs seperate power, like maybe a winch, you will have to run a new harness (winch is really a bad example, it should have a seperate power supply anyway). If you have an onboard battery on your trailer, that can eliminate some of the issues, as long as you have a charge wire for it.

The main issue I have run into lately, is people using different plugs.

The trailer that wasn't right was my dad's boat, and no one has pulled it that he hasn't wired the harness up on. Not sure if it is standard or not.

 

Before you start your wiring project, I suggest that you go to www.cummins-conversion.com then look in the towing and hauling section. there is an excellent write up on trailer wiring there.

 

Good cable plug in Patrick that is a good start, the reason I have stayed away from the butt connectors with shrink already on them is some/most don't have good double wall shrink and moisture gets in and the green gobbler eats your wire. Like I said the brakes will work better if you run a black,blue,red for power and a white directly to the terminal box which bypasses the truck frame hitch reciever connection. On a standard trailer connection there should be a white ground and 6 hot lines left,right,running lights, battery hot line, brakes which leaves you with 1 extra eg; backup however most pickups don't like the draw of extra lights on that circuit and should have a relay from the trailer hotline using the other as activator signal only. Interior lights and pumps should also be run off the battery hotline with a seperate switch as well and maybe with special applications a seperate plug and harness for just those to prevent problems. Electric brakes don't care which wire goes where just as long as it gets all the regulated power from the controller(magnets in brakes are not polarized). Most commercial lighting pig tails come White-ground, Black + for running lights so it is easy to match with the 2 wire heavy case I use Red on the plug in pigtails is your bright circuit- stop ,turn. I always wire my plug the RV flat pin standard (usually found on the back of package for plug) and make the trailer match as this is how the P/U's come from the factory. Most of the newer trucks even have the diagramn on the receptacle cover. People that wire my trailers to match their junk only use them once, ask me I will help you get your wiring right before screwing up my system. If you live anywhere that the temperature goes below freezing or just above do not even try using the flat grey wire for brake wires underneath it is way too brittle but cheap. PK

 

OK - I am still mulling over this. I hope to place my order today. I appreciate the link to del-city. While not the cheapest for EVERYTHING, I think that in ordering from only 1 place will save money and hassle over shipping from 10 different places.

I checked out the trailer and the wiring is run 100% through the frame, so I was planning on simply using a run of 18 gauge 3-wire bonded together through slit loom for stop/tail/turn, all LEDs so there is basically no current running through there. It was have minimal protection but it really doesn't need more. Then a seperate brake specific wire for the brakes.

For the below connector, does anyone have any ideas about what the diameter of this would be, to order the proper size loom clamps... ???

 

Patrick I put some pictures of the wiring and terminal boxes in my photo file, no matter what I will not caseless wiring any more. The split corrugated plastic conduit fills up with dirt and mud, gets hard in the winter and rocks chew it to pieces.PK

 

I had that on my last trailer, it was only a "pigtail to the battery and breakaway, so there was only 1 (one) insulated clamp that held it in place. The rest if the wiring on the way back was in sections of conduit.

If you've ever toyed with a screwey trailer wiring rig, you already know, as stated in earlier posts..........
Do it right the first time! Water is ongoing issue with my boat trailer. Soldering and heat shrink tubes are your friend.

 

Any idea what the stud size is on that junction box?