What are the Funtions of 7-Way Blade Style and 7-Way Round Pin Trailer Connectors

Updated 10/28/2009 | Published 10/26/2009

Question:

I am looking to build an adapter so that I can plug in a 7 pin blade Plug into a Truck but have a harness that uses a 7 pin Round Pin Plug. I just need to get the functions each pin serves on the 2 different types of 7 pin plugs I have them for the RV but do not have all of them for the round trailer plug. Can you help?

asked by: John A

Expert Reply:

When you disassemble each style of connector, you will find that each terminal is labeled by number. The 7-way round pin is wired as follows. Number 1 is the ground, 2 is the reverse lights, 3 is the left turn/brake lights, 4 is 12 volt auxiliary power, 5 is the right turn/brake light, 6 is the tail/marker light and 7 is the brake output.

The 7-way connector with the blade pins is wired differently. Terminal 1 is ground, 2 is brake output, 3 is taillights, 4 is 12 volt accessory power, 5 is left turn/brake light, 6 is right turn/brake light and the center pin is typically used for the reverse lights.

We offer an adapter that would allow you to plug a trailer with a 7-way round pin connector into a vehicle with the 7-way blade connector, part # 47595.

expert reply by: Mike L