equipment trailer wiring.

[mx842]

My junction box is mounted under the pickup. It had a factory seven pin plug and I ran the factory wiring into the junction box and ran seven wire cable back up to the plug under the bumper, and a new one to the plug in the box. I can take a picture, if you’d like. We are shelling corn right now, so I won’t be able to do that until later.

Nawh, that won't be necessary I really don't want to cut into my truck wiring. If I do install a box, I'll put it on this trailer. All my other trailers work just fine. Thanks anyway though.

 

[Rustyiron]

Nawh, that won't be necessary I really don't want to cut into my truck wiring. If I do install a box, I'll put it on this trailer. All my other trailers work just fine. Thanks anyway though.

"If it ain't broke".....
Grounding is a common problem. If doing a re wire I'll add a wire, pick up the lights and drill and tap 3 or so points along it's path. It doesn't necessarily need to go to your new splice box but it's easy enough and ties it to the truck.

 

[Too many Kubotas]

"If it ain't broke".....

Speaking of, as I'm basically rewiring a trailer that's only a couple of years old, finding all kinds of odd stuff.

For example, the wiring for charging the batteries. It was about a 30-foot run of 14 gauge, to charge two batteries. Now it'll be about 11 feet of 10 gauge, for one battery. Really should be 8 gauge, but the tow vehicle also has (too) small wire sizes leading to the trailer plugs.

Also, there were fuses on both the positive and negative wires, right at the batteries. Nothing for the hydraulic pump or compressor from the batteries to them, but at the very end of the charging wires.

Yes, it wasn't broke, but could certainly stand an improvement. Now I wish I'd measured how many volts actually made it to those batteries before I tore it all apart.

 

[LD1]

I guess they do that so when something goes wrong you have to take it to them to get it fixed. I guess I need to find out just how this truck is wired; weather it's wired 7 way traditional, or 7-way RV standard. I pretty sure it's not wired 7-way heavy duty.

AGAIN......(maybe it hasn't sunk in yet as I know this can be confusing).....

BUT... THERE IS NO DIFFERENCE BETWEEN RV STANDARD AND EQUIPMENT STANDARD WHEN IT COMES TO THE PLUGS.

THE TRUCKS AND THE TRAILERS ARE WIRED EXACTLY THE SAME WAY.

THE ONLY DIFFERENCES IS RV USES DIFFERENT COLORS

so while they use the same 6 or 7 wire colors...they use them for different things. But they still wire to the plug in the exact same spot.

Plenty of charts online that show you exactly what plug does what

 

[LouNY]

AGAIN......(maybe it hasn't sunk in yet as I know this can be confusing).....

BUT... THERE IS NO DIFFERENCE BETWEEN RV STANDARD AND EQUIPMENT STANDARD WHEN IT COMES TO THE PLUGS.

THE TRUCKS AND THE TRAILERS ARE WIRED EXACTLY THE SAME WAY.

THE ONLY DIFFERENCES IS RV USES DIFFERENT COLORS

so while they use the same 6 or 7 wire colors...they use them for different things. But they still wire to the plug in the exact same spot.

Plenty of charts online that show you exactly what plug does what

Yes, but the OP's trailer did not have the flat bladed "RV" plug on it it had the older heavy duty 7 round pin connector which is wired differently then the blade connectors.
He is going to need to wire a new end on his trailer side with the correct wires, there is nothing wrong with his truck side wiring.

 

[LD1]

Yes, but the OP's trailer did not have the flat bladed "RV" plug on it it had the older heavy duty 7 round pin connector which is wired differently then the blade connectors.
He is going to need to wire a new end on his trailer side with the correct wires, there is nothing wrong with his truck side wiring.

I agree.

But the post from the OP that I quoted and replied to said something like home needing to figure out how the truck is wired.....and whether it's RV standard or equipment.

He is still confused and think that whatever standard has something to do with the plug or truck which it don't

It ain't rocket science. You have 5 wires and a ground. Find the ground.....put 12v to the rest one at a time and see what comes on. Wire a 7-way plug and be done. Literally less than an hour provided wiring underneath trailer is good as are lights. This is just trying to make a mountain out of a molehill and overcomplicate things that really don't matter

 

[BlueKnife]

I guess they do that so when something goes wrong you have to take it to them to get it fixed. I guess I need to find out just how this truck is wired; weather it's wired 7 way traditional, or 7-way RV standard. I pretty sure it's not wired 7-way heavy duty.

No need to take it to them, unless you have no concept of how to test 12 volt electrical systems and/or have no idea how to search the internet/youtube in order to learn. If you want to know what does what in the outlet on the pickup, just test the connections. As LD1 has pointed out several times, the two 7 way flat connector wiring types are exactly the same, other than the colors. Those titles "7 way RV" and "7 way traditional" only apply to the trailer side, not the truck side. The truck side is more than likely going to have different colors than either one. You can't rely on wire color at all when diagnosing this stuff, you have to test the functions.

 

[mx842]

Ok I mis-spoke in that post I started it and had to leave for a bit and when I came back just put down what was on my mind at that time. To begin with, I'm not working on my truck. I have three other trailers that work fine hooked up to my truck. The problem lies with this new/old trailer I bought.
I guess I should also bring up that I am smart enough to search the internet and that also I was a boat mechanic for 25 years and have wired hundreds of boat trailers, so I do know a little about wiring. I never had the reason to work on simi trailers or heavy equipment trailers with electric brakes and such.
This trailer was hooked to an older Mack dump truck and from what I gather from the people that had it, everything worked ok for what they used it for. They plugged it right into the truck plugin and went on about their business.
My truck came into play because it didn't like it when I plugged it into the truck wiring. It will work fine hooked up with that heavy adaptor plug. All this started when I asked about wiring it straight. I do understand that the wire colors don't mean much with this application and I figured that out the first time I looked at the adaptor cable. What I don't understand is that damn brown jumper wire that jumps over to the black wire on the trailer plug. All I know is, with the adaptor hooked up everything works as long as I keep that jumper wire in place. If I remove it nothing works and with it hooked up straight jumped or not the truck doesn't like it. My dash displays, right turn error, left turn error, running light error. It's sending signals to the turn signals and running lights, but the signal lights flash really fast, like the older signal light switches used to do when you hooked up to a trailer. It's got to have something to do with that jumper wire. How to get rid of that is what I'm working on now.
This turned into 4 pages mainly because I try to be courteous enough to respond to what other's post to me and if that's wrong, then I'll stop doing that. I think there are a few folks here that understand what I trying to explain, and I guess it just flies over the heads of really smart people here.

 

[Peter 315]

Some semi trucks have 2 separate wires for the trailer lights tail and marker lights.. The older trucks had separate wires for brake and turn signals..

 

[Too many Kubotas]

Yes, tractor trailers and other Class 8 vehicles have those separate circuits, which is why there has to be a jumper (between 5 and 8 if memory serves me. It's been a few years) to combine the marker and taillights for use with a regular trailer's RV wiring.

If the trailer is wired to work with a vehicle that has the commercial plugs, either an adapter is needed, or changing the plug to a flat 7 and wire it accordingly.

Someone posted a chart earlier that clearly shows the differences.