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Should 12 Volt Hot Lead on 7-Way Trailer Connector Be Hot All the Time, WIll it Drain the Battery  


I was wondering if you could answer a quick question for me.I just installed the P3 brake controller that I ordered from you guys.While running the brake wire I did the 12v constant as well. At the back of my truck on the 7 way plug it has lights that show when each item is working turn,brake,stop,etc. The 12v constant stays lit at all times.Will this kill my truck battery even though nothing is hooked up?


Expert Reply:

The light that indicates that the 12 volt circuit is hot is normal and it will not drain the battery. Think of it as the battery having a really long positive terminal that just extends to the rear of the vehicle. If nothing is drawing power from it, it will not drain the battery.

If you did have a trailer connected, for example, and that trailer used the 12 volt circuit for an accessory that remained on all the time, that would draw power from the vehicle power and could potentially drain the battery. But, with nothing drawing power, you have nothing to worry about.

I have included a link to our wiring FAQ for you.

expert reply by:
Michael H

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