umbilical wire color coding

This should take care of you.
Wiring diagrams

AS both links/diagrams are good, you MUST make sure you utilize the RV diagram. All others are wrong for Rv's. Doug

It seems counter intuitive but I would never go by the diagrams for wire color alone. Use any search engine and type in "7 blade rv wiring diagram" click search and then click on images at the top of the search window. you will see many different wiring variations.

As a teenager I sold a boat to a guy and helped hook up the trailer to the truck. His 4 pin used the bare ground pin as 12v positive running lights.

Back in November I helped my neighbor replace the 7 pin on his flatbed trailer. The wire colors did not match either of the diagrams. Yes the wires went to the correct places for the plug, but the colors were wrong.

Bottom line, if you have and know how to use a multimeter, I would do two things.

1. Check in the junction box to verify the wire colors are the same on each side of the crimp or wire nut (ie. yellow wire connected to yellow wire etc). Make note if they are not.
2. Make sure the wire colors on the diagrams match your old and new plug. Use your multimeter in continuity mode to verify that the pins on the plug are the correct color at the trailer end. It only takes a second and can save some headaches troubleshooting.

Also since there is no such thing as a "STANDARD" ISO type Stanard. Just a "Tradition" you should check everything out to insure they are as listed.

A 12 volt "jump pack" battery is handy for this.. Usually they will be right but I've worked on a trailer that was anything but.

dougrainer wrote:
AS both links/diagrams are good, you MUST make sure you utilize the RV diagram. All others are wrong for Rv's. Doug

Doug, not an argument, but just to clarify as I wired mine months ago and threw out my notes when done. On the diagram above the RV diagram is the center of the three columns. This diagram shows the tail and running lights as a green wire not brown. I thought the tail and running light wire was always brown. I'm sure the memory of that difference would have stuck with me today.

opnspaces wrote:

dougrainer wrote:
AS both links/diagrams are good, you MUST make sure you utilize the RV diagram. All others are wrong for Rv's. Doug

Doug, not an argument, but just to clarify as I wired mine months ago and threw out my notes when done. On the diagram above the RV diagram is the center of the three columns. This diagram shows the tail and running lights as a green wire not brown. I thought the tail and running light wire was always brown. I'm sure the memory of that difference would have stuck with me today.

The statement I made is correct. Brown is used for NON RV trailers for running lights. The mistake people make is when they go from Boat Trailers and utility trailers with a 4 way flat plug. THAT brown wire is indeed BROWN for running lights. After 40 years and still working as a RV Tech, I think I would know what is correct:) I posted to let people know that The Internet is NOT always the most factual place to get info. In this case it WAS. BUT you had to know which of the many diagrams was correct. So, I clarified it. Doug

Fortunately both the cargo standard and the RV standard used the same locations, only the wire color changes. Just as a personal preference I always wire to the cargo standard as most outfitters are more familiar with it.

DougE wrote:
Fortunately both the cargo standard and the RV standard used the same locations, only the wire color changes. Just as a personal preference I always wire to the cargo standard as most outfitters are more familiar with it.

Explain "Most Outfitters". Who are these Outfitters? Doug

dougrainer wrote:

DougE wrote:
Fortunately both the cargo standard and the RV standard used the same locations, only the wire color changes. Just as a personal preference I always wire to the cargo standard as most outfitters are more familiar with it.

Explain "Most Outfitters". Who are these Outfitters? Doug

I meant to explain in more detail. We and I advise customers that are either towing a trailer or a vehicle, to wire the trailer and the vehicle with a 7 way Bargman trailer(male) end and WIRE it to RV 7 way code. Almost ALL motorhomes built in the past 15 years will have a Bargman 7 way RV female tow plug on the rear by the hitch. It WILL be wired as the RV Bargman 7 way code. Do NOT use a 4 way or 6 way round plug on the towed trailer/vehicle. Using the 7 way Bargman means that regardless of the new or used Motorhome you buy and use your towed vehicle will connect without any issues. For a Towed vehicle add on brake system you have the extra 2 pins on the 7 way to utilize the add on brake system wiring. Doug