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  1. #11


    You could always break that circuit with a relay that is connected to an ignition switched source.
    Myself, my beautiful wife
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  2. #12


    OK I got one for yeah.... I have a 2008 suburban hooked this up good and proper. Aux brake controller and all.

    Today I sold my old camper trailer to a couple who have a 2009 Yukon , never towed before and they just assumed that they would hook it up and all was good to go...haha , Well since i would not let the trailer go without confirming that they had brakes on the trailer. I went about and tested it power to the brakes or trailer , pop the hood and discovered that both red wires were not connected to the proper studs,dug out the wires and connected them to the proper studs and then proceeded to verify again power to the trailer wiring. still nothing at the hitch. this vehicle had a factory brake controller so i presumed it was not necessary to crawl under the dash to connect it... So pulled the fuses for the studs and verified they were good, checked power on the stud . no power . not possible you say.. well you are right. after talking to the owner of the truck, i decided that i will clean the studs. well that seemed to have done the trick. i removed the connections cleaned the studs good, tested power at the studs again . All it took was a little coat of corrosion to break the contact to prevent power to the stud. so i tested again at the hitch to make sure i had power . >>> well no i am now stumped on this last problem . maybe some one can give me an idea on what to do next.

    I have power for my brakes now but not for my aux 12 V. at the hitch. both studs at the fuse box give me 12 V. since it is a factory installed brake controller and it seems to be working i am not worried about that, but since the trailer requires a battery connection for the breakaway switch to activate the brakes in case of emergency, as well as keeping the battery charged for the aux battery in the trailer i would like to get that aux 12 volt to work.
    Did i overlook a fuse somewhere else that needs to be connected or am i leaning more toward a broken wire somewhere along the way between the front and back of the truck?

    I am hoping to help these people avoid a trip to a garage if possible. I know it is not my responsibility to fix this problem..but who can not help a fellow GM owner.

  3. #13


    Probably missing one of the J-case fuses. Check to see if there's a dummy plug (or no plug) in stud #1. That's usually the case for NBS trucks like mine ... and it's that dummy plug that needs to be removed and replaced with a 40 amp J-case fuse to supply +12v aux power to the charging pin (usually pin#4) of the 7-spade connector.

    Here's a good write-up for a NBS truck:

    NNBS trucks like yours or that Yukon may be similar... so perhaps it'll help. As I don't have a NNBS truck, myself, and have not been through this with one, I can only speculate and hope for you.

  4. #14


    thanks for the tip but i have powwer on both studs now just not on the hitch wiring. just hoped there was another fuse somewhere that needed to be activated or replaced. thanks

  5. #15


    The fuse I referred to is required to supply power to the +12v aux wire for pin 4 at the hitch in NBS trucks.

    I guess the NNBS trucks are different and don't have a fuse for it? That's surprising...
    Last edited by SurrealOne; 05-08-2013 at 10:49 PM.

  6. #16


    well as a quick fix until i can figure out if i have a break in the wire or something is not connected properly I ran a separate wire from the Stud direct to pin 4 and all is working as it should.

  7. #17
    Jr. Engineer Jaele's Avatar
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    Nov 2011
    Fairfield CA


    You are correct, its hidden under the dash for an aftermarket break controller.
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