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Random wire by engine bay fuse box

Discussion in 'GM Electrical Tech' started by justaphase44, Jan 18, 2013.

  1. justaphase44

    justaphase44 New Member

    hey guys, went to pull my drl fuse and noticed this random wire connection by the fuse box. Any suggestions/comments on what it may be for? Truck is a 2012 Sierra SLE All Terrain. (And no, I haven't installed any aftermarket wiring or had anything installed btw)

    Attached Files:

  2. TRPLXL2

    TRPLXL2 New Member Platinum Contributor 1000 Posts 100 Posts

    I have not purchased a new vehicle since 2005, so don't take this seriously but if I had to take a guess, I would say its the fuel pump prime/test wire. My firebird and Colorado have one, not sure if the big trucks do? It looks to be pretty thick, so that's what made me think that.

    Free bump to the top!!
  3. Enkeiavalanche

    Enkeiavalanche Moderator 1000 Posts 100 Posts

    Your trailer Hot lead.. If you have a camper hooked up with a Battery you would hook up that wire to charge it.
  4. TRPLXL2

    TRPLXL2 New Member Platinum Contributor 1000 Posts 100 Posts

    Ooops ha ha!!! Well I learned something new, that is a really cool idea!!
  5. zigger215

    zigger215 New Member 100 Posts

    +1. Always beatin me to the punch enkei
  6. justaphase44

    justaphase44 New Member

    I had no idea, thanks for the replies. Much appreciated
  7. Enkeiavalanche

    Enkeiavalanche Moderator 1000 Posts 100 Posts

    Thats what we are here for..... :glasses:
  8. tbplus10

    tbplus10 Super Moderator Staff Member Platinum Contributor 1000 Posts 100 Posts

    Yep trailer hot lead.
    When I bought my truck last year I spotted that wire and the salesman couldnt tell me what it was for, I refused to sign for the truck until they got a service tech to come out and show me in the GM maintenance manual what it's purpose was.
  9. jake's silverado

    jake's silverado New Member 100 Posts

    There are actually 2 wires that are like this under the hood if my memory serves me right. The one you spotted and then there is another for the electric brakes. On my 2007 NBS they were not connected to their posts at the front of the fuse box seen in your picture. as well there was no fuses in the fuse box for them. So to connect these you will need the 2 nuts(ahem) and the 2 fuses. I will look for a picture I had of where the other wire was located, i think it was the other side of the fuse box down low in a harness. If I find it I will send you a note if you are interested.

    on my 2011 HD they came all hooked up and ready to go!
    Found it!
    Send me a PM with your E-mail address and I'll send you a an adobe PDF file with the random wire hook up I have. If you want!
    Picture1.jpg

    For the wire you found
    Place terminal on larger of the two studs at front of electrical center and secure with M8 nut.
    Picture3.jpg
    Last edited: Jan 19, 2013

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