I’ve seen some videos and tried to understand this as best as possible.
My camper has a 7 pin connector, some type of converter box with a 110v wire for shore power and a 110v outlet on the box.
There is a mess of wires in the trailer and there’s only a light fuse, water pump fuse and heater fuse, I don’t get why there’s so many wires.
The 7 pin harness is crumbling and the mess of wires is well, a mess.
I’ve drawn up this wiring diagram. Per the videos I saw, this diagram looks correct. A video I saw showed a breaker box that plugs into shore power and then the converter plugs into that breaker box-in line to shore power. I can just plug the converter right into shore power and run 12v to all accessories, yea? The diagram does not include any 110v outlets. I don’t think I will need any.
Here’s the diagram typed out.
Converter box: +12v to to 12v fuse box Ground to ground bus bar
2 batteries wired in parallel: Ground to ground bus bar 12v+ to fuse box with a kill switch to shut off all power to trailer when not in use 12v+ in line Reseting breaker
Ground bus bar: Interior lights Exterior lights Water pump Misc. items
7 pin connector on the truck: 12+ auxiliary to fuse box Ground to ground bus bar 5 other wires for each of the lights.
Some concerns, Biggest one, does this look correct? The video I saw used breakers in a breaker box. The converter box I am looking at only has 2 small fuses on it. Is this ok? The Ground wire from the 7 pin was said to go to the ground bus bar for charging the batteries, how will the trailer lights ground and function? There is no chassis/frame ground, do I add one? If so from where?
Your diagram is close. Yes add grounds, cleanly bolted to the trailer frame. You will need a separate breaker box if using the converter, as it doesn't include them. The trailer should already have a 110 breaker or fuse box. Are you SURE there are no 110 outlets? Maybe on the light fixtures? I've not seen a trailer without at leas one outlet...
GROUNDS: The grounds are extremely important in our trailers. There should be a dedicated ground from the breaker box to the trailer frame. Since you will be using a converter, this dedicated ground will serve as a ground for the converter box itself. (instead of a stand alone breaker box) The battery should be cleanly grounded to the trailer frame. The battery ground bolt can also be used to run into the trailer to your ground bracket/bar. Also, I run a ground into my tongue junction box from the trailer frame. Then I connect the brake ground, the trailer cabin ground and the 7 way ground wire to the frame ground. Your grounds can never be too many; when in doubt, ground it again. This includes skin to frame grounds if necessary. The 7 way white ground wire is connected to the vehicle frame near the receptacle.
Here is a correct diagram:
<a data-flickr-embed="true" href="https://www.flickr.com/photos/53634851@N03/34828339513/in/album-72157683590489800/" title="12 Volt System Diagram"><img src="https://live.staticflickr.com/4229/34828339513_425481a348_z.jpg" width="640" height="465" alt="12 Volt System Diagram"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
The middle or back up pole is not used unless your trailer has back up lights.
Here are the parts for the tongue area J box:
<a data-flickr-embed="true" href="https://www.flickr.com/photos/53634851@N03/35250424210/in/album-72157683590489800/" title="12 Votl Parts 4"><img src="https://live.staticflickr.com/4205/35250424210_e61d6a2503_z.jpg" width="640" height="427" alt="12 Votl Parts 4"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
Here is a close up of the J box wiring: <a data-flickr-embed="true" href="https://www.flickr.com/photos/53634851@N03/34828340423/in/album-72157683590489800/" title="Junction Box 1"><img src="https://live.staticflickr.com/4002/34828340423_6314da2796_z.jpg" width="640" height="427" alt="Junction Box 1"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
Hey Vikx, thanks for the reply and the help. Greatly appreciated as it’s hard to find this info online. I cannot get your images to work for some reason though..? Are my images working?
The trailer currently has some type of breaker/converter box. I am not sure. The box has a 115v outlet and a breaker reset button for the 115v and the 12v system. There is a small 12v fuse box with 3 fuses. I don’t see anything else besides random wires.
My original diagram, the one I posted above, did not include a breaker box. I didn’t see a need for 110v outlets and from what I’ve seen in videos, the breaker box is a middle man with 110v outlets.
I’ve decided to add a breaker box so I can have 2 110v outlets and I added it to my diagram. I added grounds to some items, I’m not sure if they are necessary.
This is the diagram typed out. It’s almost the same as before.
Converter box: 12v output to 12v fuse box Ground output to ground bus bar
2 batteries wired in parallel: Ground terminal to ground bus bar 12v terminal to 12v fuse box with inline kill switch and inline resetting self breaker
Fuse box: 12v wire to interior lights 12v wire to exterior lights 12v wire to water pump 13v wire to Misc. items
Ground bus bar: Ground to interior lights Ground to exterior lights Ground to water pump Ground to Misc. items Ground to copper propane line Ground to trailer frame and trailer skin
7 pin connector: 12v auxiliary wire to 12v fuse box Ground wire to ground bus bar and to trailer frame 5 colored wires for each light Inline fuses for each light on the 5 wires
Breaker box: Breaker box grounded to trailer frame and trailer skin Breaker box output to 2 110v outlets Break box output to shore power with 30 amp plug
I THINK this is correct.
My only questions (the more I read, the more questions come up) Are all my grounds in the correct location?
Since the ground bus bar will be grounded to the frame, no need to run my 12v lights or water pump to the ground bar right? Just ground them on the frame?
I do not have a battery ground terminal direct to frame in my diagram. In a sense, it grounds to the frame through the ground bar. Should I add a thick ground cable from battery negative terminal to the frame?
The converter will be plugged into a 110v outlet on the breaker box. The circuit breakers are to cut all shore power to the converter right? Unplugging the converter from the 110v outlet should cut all shore power too, without having to flip the breakers right?
The trailer currently has an ON/OFF switch labeled “Truck battery”
What is this switch for? Is it the kill switch to cut off all power from the battery?
You mention a ground for your electric brakes, is this the ground wire on the 7 pin harness? I still need to add a break away switch to the diagram, but I will do that near the end when I’m sure my diagrams are correct.
Here’s a photo of my new diagram as well as the converter box I currently have(will be getting a new one) and the truck ON/OFF switch in the trailer.
All images are showing for me. Try re-loading the page and they should pop up. It sometimes takes a while.
Your converter BOX is a very light duty load center, similar to what is found in tent/pop up trailers. It looks to include 110 breakers and a 12 volt set of wires. If there are fuses, you do not need any cut off switches. Just remove a fuse. The converter box should have a dedicated ground to the trailer frame. You can add grounds but do not rely on the ground bar for the converter box; ground it to the trailer frame. There should also be a separate ground from the ground bar to the trailer frame.
You can ground the 12 volt fixtures to the frame or ground bar, whichever is handiest. There's no need for a single ground for each item, they can be junctioned together in J boxes as you run the wires. There could be a J box for the upper wires, one in the closet and probably one in the dinette. The skins are usually grounded with a small wire from the skin to the frame.
There should be at least a 12ga brake ground to the trailer frame. The brake hot connects to the blue 7 way wire in the tongue J box. The breakaway will have 2 black wires; one joins the blue wire and brake hot, the other is connected to the battery hot.
I have never grounded a propane line and have never seen that, so it should be skipped. The heavy duty battery negative wire should be grounded to the frame. The hot joins the trailer hot in the tongue J box and then goes up and into the trailer fuse box.
I'm not understanding 5 wires to each light. A 12 volt light needs one ground wire and one hot wire from the 12 volt fuse box. If you want to connect the wires together, use electrical wing nuts to connect and run to the next light. I'm also not understanding why you are including a backup light wire unless your trailer has backup lights. Most do not.
I'm guessing the truck on/off switch runs the 12 volt side of things off the truck battery when on.
My thought on the above is to slow down and take your time. You need photos of what is to happen rather than videos. It's much easier to view a photo than find a place in a video. I would start with your 12 volt junction box near the tongue and run the 7 way cord into that and clamp it. Do your grounds (1/4" bolts and ring terminals work fine-bare metal on the frame) and plan where/how you will run up and into the trailer.
We can work forward from there.
PM me for my email address if you can't view the photos.
I got the images to work now. For some reason, the links were very long and I had to find the correct part of the link that would show me the image.
There is glass type fuses in the trailer, but there’s also random wires through out it. I only have 3 circuits right now, water pump, lights, and heater, so I don’t get why there’s a bunch of other wires. I was planning on buying a new converter and running all new wiring.
Do you think this converter box will be fine to use? It seemed to work when plugged into shore power with the 110v cord and the 12v system also worked when I hooked up a battery. That will save me some money. I will make sure to add a separate ground wire from the converter box to the trailer frame. I had already included a ground wire from the negative bus bar to the trailer frame.
I am going to pull out the converter and see what input terminals it has. As far as I know, I just need the 110v cord that plugs into the breaker box, and a negative and positive output right? Basically 2 terminals and the 110v cord…?
I will most likely ground each 12v accessory to the frame to avoid excess wiring and run the on/off switches on the 12v side.
I see what you’re saying about the brakes. The brakes have 2 wires, I had not included the axle itself in my diagram. The 12v brake wire on the 7pin harness goes to 1 brake wire and the second brake wire goes straight to the trailer frame correct?.
I will add a thick ground cable from the battery negative terminal to the frame as well.
The 5 wires I mentioned were meant to be 5 individual wires for the lights. Rather than typing right signal, left signal etc etc. I have the reverse lights in the diagram so I don’t forget. The lights on the trailer are also no good. I’ll be getting a new light set, I may add reverse lights. I am not sure on that yet.
The truck ON/OFF, I’m not sure if I need that. I won’t be using that switch, just replacing it with a new one. But I’m not sure what wire it is suppose to break…?
I am looking at your photos and it makes my diagram look like a mess because everything is all over the place. I will re make it and post it back.
I based my digram off of Vikx pictures. Mine just looks more complicated.
1 more revision I’ve made is that, instead of the breakaway hot wire going to the fuse box, I will wire it to directly to battery +.
Now does it all look correct? Will my batteries charge when the truck is running and will then also charge when plugged into shore power?
Should I run the 7 pin +/- to the batteries first and then to the junction box? Or run 7 pin +/- to junction box and then to the batteries?
I would prefer the 7 pin 12v to go to the fuse box in the trailer and then to the battery. This way I can have a kill switch inside the trailer that cuts off all power from the battery instead of having the switch outside.
Your wire connections are not complete so I'm guessing here:
The 12 volt hot from the battery goes to the self resetting circuit breaker "batt" stud. (in the J box) The inside trailer hot goes from the circuit breaker "aux" stud to the fuse block hot stud. The converter hot goes to the same inside fuse block stud. This will charge your batteries when on shore power.
The 7 way cord black wire goes to the circuit breaker BATT stud. This will charge your battery when on the road. NOTE: the 7 way vehicle receptacle must have the 12 volt hot connected to your vehicle battery via a fused line.
You can add kill switches or fuses to the hot lines. They are not necessary on tow wires, since they are fused from the vehicle. The more fuses, breakers and kills inline, the more apt to cause future troubles.
One break away wire connects to the battery hot. It should not have a fuse or breaker inline; it goes directly to the BATTERY HOT. The other break away wire connects to the brake hot wire inside the J box.
Be sure to follow instructions for your converter on wire gauge and connections.
Your truck may or may not have a hot wire run to the 7 way receptacle. Some trucks need to have a fuse installed for it to be hot. Factory wired trucks usually do not need a fused wire from the battery.
You do not need to shut off anything for the converter to work on shore power. Likewise, when it's off, the battery takes over and runs the 12 volt items in your trailer.
Also, do not add the backup light wire unless the trailer has backup lights.
My truck has the factory tow package with the 7 pin connector. I’m sure it has a 12v wire, but will verify it near the end.
I think I’ve got the digram finalized. I’ve looked at my previous 5 diagrams, looked at your diagrams and here it is. How does it look now? I’ve also added the breaker box wiring.
Here’s the digram written out.
7 pin harness from the truck: Right signal Left signal Running lights Electric brake Hot to brakes Reverse lights-I will probably add some, if not I will leave it empty. 12v wire to circuit breaker in J-Box-Batt stud Ground to J-Box
2 batteries wired in parallel: 1 negative terminal to frame/skin ground 1 negative terminal to ground in J-Box 1 positive terminal to J-Box circuit breaker-Batt stud
Circuit breaker: Batt stud to battery positive terminal Batt stud to 7pin 12v Aux stud to fuse box WITH an inline kill switch
12v Fuse box: 1 stud will go to Aux stud on circuit breaker The same stud goes to the converter positive Fuses feeding 12v accessories
Ground bus bar: Ground to J-box ground Ground to frame/skin Ground to converter
Converter: 12v to stud on fuse box Ground to ground bus bar Converter box grounded to frame/skin Converter 110v plug to plug into breaker box/outlet
Breakaway switch: Wire 1 to battery positive Wire 2 to to brake hot wire on 7 pin harness
Junction box: Circuit breaker Ground terminal
Breaker box: 2 breakers 3 neutral wires with a wire nut- 2 wires to 110v outlets- 1 wire to shore power plug
3 Hot wires- 2 wires to 110v outlets- 1 wire jumping both breakers to shore power plug
4 ground wires- 2 wires to 110v outlets- 1 wire to shore power plug- 1 wire to frame ground.
The kill switch between the circuit breaker Aux stud and the fuse box is to cut all power to the trailer while driving, but still send charge to the batteries.
The inline fuse on the HOT 12v 7 pin is to make it easier to replace the fuse rather than look through the fuse box on the truck.
The 12 volt and tow wiring seem good. The breaker box is not correct.
The box should have a ground bar and a common bar. Commons and Hot wires are NEVER joined together in an RV. The box also has one hot lug or two hot lugs, depending on whether it is 110/120 only or 220/240.
The shore power wires enter the breaker box and attach as follows: Ground wire to ground bar. Common/white wire to common bar. (this bar is isolated from a metal box to keep it separate from the grounds) The hot wire goes to the hot lug. If the box is capable of 220, the TWO lugs are joined with a 10ga. jumper.
The breakers are never joined together. Each has a single hot connection going OUT to a separate circuit. In other words, the shore power hot powers the breaker bar. Each breaker then powers an individual circuit when flipped on.
Here is a properly wired breaker box:
<a data-flickr-embed="true" href="https://www.flickr.com/photos/53634851@N03/46795849444/in/album-72157682956476004/" title="006 g Breaker Box (1)"><img src="https://live.staticflickr.com/7816/46795849444_ca745f0763_z.jpg" width="480" height="640" alt="006 g Breaker Box (1)"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
Orange is the shore power cable coming into the box. The two hot lugs are jumpered in this box and the shore hot lead connects to one lug. Grounds on the left, commons on the right. The two black wires at the bottom of the breakers go out to each circuit.
Please do heavy research before wiring the breaker box and if necessary, hire a qualified electrician to do the work or inspect it. Electric is nothing to mess with and can lead to catastrophic damages or injury.