Which Wires Have Constant 12V Power on a 7-Way Connector

Published 07/14/2021

Products Featured in This Question

7-Way Round RV Style Trailer Connector - Trailer Side

(375)

$13.57

Hook Probe Circuit Tester

(60)

$12.41

Question:

On my 2008 F2 5710 harness is any other wires constant 12 V

asked by: Jeff

Expert Reply:

For your 7-way trailer connector, the only wire that might have constant power is the one running from the 12V power pin and battery. Since some vehicles always have power and some do not it is not possible to determine this for your 2008 F-250 Super Duty without testing.

Using a circuit tester like the # PTW2993 Hook Probe Circuit Tester, you can test the pin in the one o'clock position on the 7-way connector. This should be the 12V hot lead. Other pins should not have power unless the light connected to them is used or if the brakes are applied but you could test them as well.

I have attached a review video of the circuit tester as well as a diagram of the 7-way connector for your reference.

expert reply by: Robin H