Horn not working

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Seirann, Sep 4, 2025 at 1:00 PM.

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  1. Seirann

    Seirann New Member

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    Vehicle:
    2013 Prius
    Model:
    Three
    So I recently bought a 2013 Prius and it's running fine, but whenever I tried to use my horn, it just doesn't sound, if the car is started or not it just doesn't have any sound. I went to a mechanic, they said it is the relay, whenever I try to look up where the relay is located all I get is that it is built into the white strip called the junction block or integration relay. I took that thing out it is just a pcb and it is not serviceable, I would need to just a whole new junction block. The mechanic instead quoted me for a HOLSTEIN 2RSW1004 relay which I can't seem to find where it would plug in. I will try to buy a new fuse for the horn and see if that fixes it, but in the mean time I want to ask you, the prius gods help me with fixing my horn.

    Details about the car:
    odo : 159k miles
    was in a crash, the right side of the car was a bit damaged, no structural damage tho
    it did have a loose connection on the positive terminal on the battery that i later fixed
    the guy i bought it from said it passed inspection but it wouldn't pass inspection without the horn
     
    #1 Seirann, Sep 4, 2025 at 1:00 PM
  2. bisco

    bisco cookie crumbler

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    try ebay or salvage
     
    #2 bisco, Sep 4, 2025 at 9:52 PM
  3. Tombukt2

    Tombukt2 Senior Member

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    Been thru this on this model w turn signals dinged wire behind bumper cover wer it was hit. Probably similar in this hit model . Always is.
     
    #3 Tombukt2, Sep 5, 2025 at 9:14 AM
  4. ChapmanF

    ChapmanF Senior Member

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    Model:
    IV
    Troubleshooting a horn circuit with a relay is straightforward. There's a wire from your steering column to the relay, there's power that comes to the relay, and there are wires from the relay to the two horns.

    If you stick a meter where the wire from the steering column connects to the relay, and that wire doesn't go to ground when you press the steering pad, the problem is between the steering pad and the relay.

    If the trigger wire to the relay does go to ground and the horns don't honk, next you'd normally check with a meter that the power coming to the relay is there. In the case of the long white integration relay, there are some other things that also wouldn't be working if it isn't getting power, so it probably is.

    So you stick a meter on the wires to the horns where they plug into the relay. If you see +12 when trying to honk, but nothing honks, then there's a problem with that wiring or with the horns.

    If it doesn't go to +12, you replace the integration relay. It's under $100 at Toyota dealers that discount. I'd consider it worth that much in avoided headaches compared to trying to mod the fusebox and shoehorn some other relay in.

    The Electrical Wiring Diagram shows how to locate all the points I mentioned testing with a meter above. Toyota Service Information and Where To Find It | PriusChat
     
    #4 ChapmanF, Sep 5, 2025 at 10:31 AM
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