7 pin black hot wire

[Ramsey]

Hopefully someone can shed some light on my question. I just had a brake controller installed on my scamp and in the process had a 7 pin TV plug added to connect with the trailer. I now have trailer brakes. Installer also wired in the hot black wire which i believe is normally used to charge the trailer battery while in transit?? I do not have a converter/charger in the Scamp. What purpose does the black wire serve in this instance. Any light as to what i have going on would be appreciated.......
thanks, Ramsey

[Rick Mooyman]

It is wired to the + side of the trailer battery and you take the white ground and splice a wire to the - on the battery. If you don't have a battery then it will not be wired to anything on the trailer side.

[Ramsey]

Thanks Rick for your response. So you are saying to splice or tap into the white wire in the trailer wiring and run it to the negative post on the trailer battery and that is all that is necessary to enable charging?

[Rick Mooyman]

[Robert Johans]

Though the POLE positions may be correct, my experience with 7pin wiring tells me that the color coding on Rick's illustration could be confusing and is not exactly indicative of the trailer's WIRE colors that I have seen.

perhaps not universal, nevertheless here are the 7 wire colors and applications of all the trailers I have worked on:

Black = 12vdc + (power)
White = 12vdc - (ground)
Green = running and taillights
Red = left turn signal and brake lights
Brown = right turn signal and brake lights
Blue = electric brakes
Yellow = auxiliary