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The horn on my 2011 Nissan Cube no longer works. Since it has never been a good horn (it's too soft), I figured that it would be good to replace it anyway.

I have tested that the horn relay clicks when I press the horn button on the steering wheel, and I have used my multimeter to verify that the 10amp horn fuse is still good.

I removed the horn from behind the bumper and used my multimeter to verify that the spade connectors for the horn are receiving 12 volts when I press the horn button.

However, when I hooked up the new horn and wanted to test it before I close everything up, it also doesn't work!

I used my jump pack (JNC660) and some test leads to make sure the new horn was not defective, and it worked properly. Then I used the jump pack to test the old horn, and it also worked!

If I have tested that the horn switch, horn relay, horn fuse, and horn are all working, and that the horn terminals have 12v when energized, why does the horn not sound? What else can I check?

(Note: I have the service manual, and it does not have any useful information. The wiring diagrams verify that everything I have tested is correct, and there are no instructions other than for physical removal/replacement.)

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    It's safe to say that the premise in the title is incorrect ;-). Mar 14, 2022 at 7:11
  • @Peter-ReinstateMonica When I tested it, it was working.
    – Moshe Katz
    Mar 14, 2022 at 15:38
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    Are you sure the horn power is able to complete the round trip? Mar 14, 2022 at 19:51
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    @Harper-ReinstateMonica The horn has two spade terminals - when I tested originally, I put the multimeter leads in both of those and had a complete circuit. I found that it was a bad ground when my 6-year-old asked me if he could "help" and I told him to watch the multimeter while I pressed the horn. He pulled on the wires when he moved the multimeter, causing the circuit to break. As mentioned in my comment below, I ran a new ground wire and it is working perfectly now.
    – Moshe Katz
    Mar 14, 2022 at 19:59
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    @EJoshuaS-StandwithUkraine That's not true. The real problem is the blind spot that fails to account for all of the parts - in this case, the wires an their connections. They were not tested. They are a "part".
    – J...
    Mar 15, 2022 at 14:18

1 Answer 1

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Couple things to try,

  • Check the ground for horn
  • Remove the relay and run a jumper wire between 30 & 87 terminals where the relay should be. If this works then your relay is bad.
  • Use a 12V test lamp in place of the horn for now so its easier to diagnose whats going on.

Just because a dmm reads 12V doesn't necessarily mean there is any current coming through. You need to test for voltage while its under load (e.g. with 12V lamp connected)

Whats the year & model?

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    Turns out it was an intermittently bad ground. I ran a new wire instead of trying to re-crimp the spade terminal on the old wire.
    – Moshe Katz
    Mar 13, 2022 at 23:09
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    When I worked in a motorcycle store spares dept I used to test horns by touching the wires directly to a spare battery. Used to make people jump. Mar 14, 2022 at 20:24

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