7 blade trailer plug

[kbenz]

I was looking up 7 blade wiring diagrams. I didn’t realize there were different variations of it. Is there an actual standard for it? Or most common at least

 

[MadMac]

Yes, apparently there is a standard SAE J2863. There are three minor revisions which are of no real consequence. There are four major seven connector plug types, of which what we all use... is the 7-Way RV Blade (Standard – SAE J2863 / SAE J1239).

I fished this out with ChatGPT, and a bit of other research:

Most common in North America (light-duty trucks, SUVs, travel trailers)
Flat, rectangular blades
Plug shape: Round body with flat blade pins
Female plug on vehicle, male on trailer
Pinout (clockwise from top center pin):

Pin	Function	Wire Color (typical)
1	Ground	White
2	Tail / Marker Lights	Brown
3	Left Turn / Brake	Yellow
4	Battery Charge / +12V	Black
5	Electric Brakes	Blue
6	Right Turn / Brake	Green
7	Reverse Lights / Aux	Purple / Red

The others are:
2. 7-Way Round Pin (Commercial / Agricultural / Military)
• Round pins (not flat blades)
• Often found on semi trucks, farm equipment, military trailers
• Same 7 functions, but:
• Different pin shapes
• Different pin assignments (depending on usage)
• Not interchangeable with 7-blade RV sockets

⸻

3. 7-Way Flat Pin (Obsolete / Rare)
• Flat pins arranged linearly in a rectangle
• Occasionally used in older utility trailers or European conversions
• Mostly deprecated in favor of 7-blade or 6/4-pin connectors

⸻

4. ISO 1724 (European 7-pin Round)
• Common in Europe, not compatible with U.S. plugs
• Round with small round pins
• 12V system but with different function assignments
• Caution: Never assume plug compatibility between EU and U.S.

 

[onetonjohn]

Was just looking at this. This was helpful for me: https://www.etrailer.com/faq-wiring.aspx Probably same info as mad mac just posted, only it's got some pretty pictures.