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oem 5th wheel / gooseneck wiring

Discussion in 'Towing & Trailer Tech' started by 03 SIERRA, Jan 24, 2013.

  1. 03 SIERRA

    03 SIERRA Rockstar

    did you know that some 08 and up silverados / sierras have oem 5th wheel / gooseneck wiring? its up under the bed near the fuel tank inlet. i think its only on the vehicles with the complete tow package hitch, tow mirrors, brake controller. just some food for thought. no more butchering the oem harness to get a 7 way in the bed.
  2. Crawdaddy

    Crawdaddy Epic Member Staff Member 5+ Years 1000 Posts Platinum Contributor

    That's handy information. I think I've read before that it's tucked up either over the fuel tank as you mentioned or over the spare tire.
  3. geo70brem

    geo70brem New Member

    5th wheel harness

    I looked for the harness under my 2004 HD and couldn't find it. I was told that if the trailer plug was already at the rear bumper there was not another harness tap under the truck. Anyone else know about this?
  4. 03 SIERRA

    03 SIERRA Rockstar

  5. geo70brem

    geo70brem New Member

    Thanks for the advice. I was looking for an aftermarket harness of some sort. This seems to be just what I need. I have moved the factory plug into the bed for my 5th wheel but i still need a plug outside for a boat trailer. I thought there was something out there but couldn't find it.
  6. steved

    steved Former Member


    You will have an extra option on the window sticker for camper/5th wheel wiring @ $25...it isn't part of the basic towing package.
  7. 03 SIERRA

    03 SIERRA Rockstar

    yeah thats right. there is probably a code in the glove box. i do not know what the code is though.
  8. 03 SIERRA

    03 SIERRA Rockstar

    i have confirmed 99-07 trucks do have this option.
    this applies to all 3/4 ton and up trucks 99-current if you look under the back of the truck, follow the wiring from the back of the 7 way if it does not come directly from the wiring harness on the frame you will notice an identical plug like on the back of the 7 way. it will tee off and run to the front of the gas tank clipped to the bed mount bracket on the frame.

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