7 pin wiring

Mowermech is correct, you can wire it up anyway that you want, as long as all the lights work. But......If you plan to get a new trailer, plan to get a new truck or ever imagine towing a friend's trailer it is far easier to wire them up by the standards.

This happened to me and it was a real pain. I had a trailer that "worked" but then I purchased a new trailer and I had them both for a short time. It was almost impossible to tow them. And, one time I camped with a friend who had a boat that he towed behind a MH. At the lake we would drag the boat to the lake with my truck. Guess what? What a mess. I will never do that again.

Bargman and Hopkins have published a "standard", but in reality it is more of a "gentleman's agreement". You can wire your trailer anyway you want to. There is no official agency that will write you a ticket for violating the "standard".
It pays to follow the Bargman/Hopkins diagrams, so everything is the same, but it is not required by law or regulation.

https://www.google.com/search?q=bargman+rv+trailer+wiring+diagram&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwifoNTpwpbUAhUIsVQKHfbbDAgQsAQIIw&biw=1536&bih=731

Ok, sgt! Always learning.

Tell the local service center to wire the plug the standard way. If they don't know what that is find a new shop. Yes, they're standardized.

Freightliner chassis, they do all the wiring.

"bought a Jeep Grand Cherokee that I am having set up for towing at a local service center. "

Then "I can't find what the 7pin wiring diagram is on the MH."

The Jeep will be towed? By the motorhome...oh.

How does Freightliner figure into this?

RoyB is correct. Click here for everything you want to know about trailer wiring. :)
Barney

Etrailer is where I got all my stuff for the toad. I did check there first and that is where I found the "standard" diagram. Thanks

Read up everything about 7-way connectors and wiring on ETRAILER.com

Roy Ken

They are indeed standardized.