Troubleshooting Trailer Brakes and Brake and Turn Lights Not Functioning With 7- to 6-Way Adpater

Question:

vehicle has a six round and trailer has a six blade plug We re only getting running lights Vehicle: Ford F350 Trailer: Gooseneck

asked by: Edwin M

Helpful Expert Reply:

First, I recommend testing the 6-pin round connector on your Ford F-350 to ensure it is functioning correctly. You can use a circuit tester, like # PTW2993, to test the functions at each pin.

The pin at the 12 o'clock position should have constant signal for the taillights and running lights. The pin at the 2 o'clock position is for the ground wire. The 5 o'clock position is for left turn and stop. The 7 o'clock pin is for right turn and stop. The 10 o'clock pin is for the brake controller output, and the center pin is for 12V power. It is easiest to have a helper when testing the connector so one person can be in the cab of the truck to press the brake and activate turn signals while the other tests the functions at the connector.

If the connector on your vehicle is functioning properly, you will also want to test the adapter you are using to make sure it is wired correctly and working properly. I have attached wiring diagrams showing how the 6-pin vehicle and trailer side connectors and the 7-way vehicle and trailer side connectors are wired, as well as a help article on trailer wiring for you.

If you need a new adapter, the Hopkins Adapter 6-Pole to 7-Way # 47435 that you referenced is a great choice. Another option is to wire your own adapter. For a trailer side 6-pin and vehicle side 7-way blade connector for a new adapter, I recommend using the Pollak Replacement 7-Ways # PK11893 and the Hopkins 6-Way Molded Trailer Wire Connector # H20036. You will want to wire the trailer side 6-pin to the 7-way connector function-for-function.

When looking at the back side of the 7-way trailer connector, the white wire from the # H20036 will connect at the 5 o'clock position, the brown wire will connect at the 1 o'clock position, the green wire will connect at the 9 o'clock position, the yellow wire will connect at the 3 o'clock position, the red wire will connect at the 7 o'clock position, and the black wire will connect at the 11 o'clock position.

If you do not need the reverse light function on your trailer, you can eliminate the need for the adapter by changing out the 7-way connector on your trailer for a 6-pin connector like # H20036.