How to Make a 5-Way Round Pin to 7-Way Round Pin Trailer Connector Adapter

Question:

Do sell an adptor that converts a 5 pin round to a 7 pole round?

asked by: Ed D

Expert Reply:

A 5-Way Round to 7-Way Round trailer adapter is not available, but I can tell you how to make one and what you will need.

If the 5-Way round is on the vehicle, you will need the following:

5-Pole, Round Pin Trailer Wiring Connector, # PK11501
7-Pole, Round Pin Trailer Wiring Socket, # PK11720
7-Pole Rubber Socket Boot, # PK11761
Jacketed 6 Wire - per foot, # DW04906-1 (get 2 feet worth)

Start by testing the functions of the 5-Way with a circuit tester, # PTW2993 if needed. Once you know the functions of the pins, you can attach the wire to the connections inside the 5-Pole, Round Pin Trailer Wiring Connector, # PK11501, using the Jacketed 6 Wire - per foot, # DW04906-1.

Attach the white wire to the ground pin, the yellow wire to left turn/brake light pin, green wire to right turn/brake light pin, brown wire to running light pin. The last function could be a number of things, but go ahead and attach the blue wire to the last pin. Once the connections are made, close up the connector.

On the other end of the wiring, slip on the 7-Pole Rubber Socket Boot, # PK11761, backwards as it will be inserted into the 7-Way at the end. Make the following wiring connections to the 7-Pole, Round Pin Trailer Wiring Socket, # PK11720 (if looking at where the wires attach):

Yellow wire to pin in 8 oclock position
Green wire to pin in 4 oclock position
Brown wire to pin in 2 oclock position
White wire to pin in 12 oclock position
Blue wire, depending on the function: if it carries 12 volt power, attach to 10 oclock position. If it carriers brake controller output for electric brakes, center pin. If it is for reverse lights of a reverse lockout, 6 oclock position. The extra wire in the wiring is not needed.

After making the wiring connections, slide the boot in position. You made need to tape up any gaps using electrical tape.

If the Vehicle has the 7-Way round, and the 5-Pole is on the trailer, you will follow the same method described above but use 7-Pole, Round Pin, Trailer Wiring Connector, # PK11700, to plug into the vehicle, and use 5-Pole, Round Pin Trailer Wiring Socket, # PK11502, for the trailer to plug into.

I have included a link to our wiring FAQ that might also help.