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Horn Circuit Question

Discussion in 'GM Electrical Tech' started by Macattac3572, Sep 4, 2012.

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  1. Macattac3572

    Macattac3572 New Member

    I installed an Air horn on my truck, at the same time I installed a compressor, solenoid valve, horn relay, and a push button switch. Currently it is not wired into my vehicle horn relay, and that is what I am now trying to do. I am trying to contain the wiring to the inside of my cab. I have put a multimeter on 3 different wires that I think go to the horn switch and I get no voltage. When I look for a schematic for the horn circuit all I find is for a 2003 Silverado, my truck is a 2007 Silverado, I would think that the schematic would be close. The question that I have is; Does the wire running from the factory horn relay going to the horn switch have 12 VDC power or is this a negative wire just providing a ground. My current wiring schematic for the air horn is set up as required for the Wolo Solenoid valve and I want to run a jumper wire from my horn switch wire to the back side of my air horn so that when I hit my regular horn the air horn goes off as well. In order to do this I need the 12 VDC to open the solenoid valve.

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    Last edited: Sep 4, 2012
  2. Macattac3572

    Macattac3572 New Member

    After doing some more research, on the 2007 NNBS Silverados there is no horn relay, well there is but, it is a printed circuit board. At this point I am going to run a wire from my switch and splice into the horn power wire close to the factory horn. I believe that the wire running to the horn switch is just a ground wire with no power.
  3. moogvo

    moogvo Moderator 1000 Posts 100 Posts

    I would suggest that you use your own relay to avoid burning wires or contacts.
  4. Macattac3572

    Macattac3572 New Member

    Thank you, that is what I was going to do. Would rather be safe than sorry.
  5. Chris Miller

    Chris Miller New Member 100 Posts

    Just put it on its own circuit, separate from the horn, with its own push button. That way you'll at least have use of your regular horn too.
  6. moogvo

    moogvo Moderator 1000 Posts 100 Posts

    Why not run the existing wire that runs to the horn to a relay and use the relay to power the horn air valve? That way, you can switch it back with no problems.

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