1. Attachments are working again! Check out this thread for more details and to report any other bugs.

My horn will not give a long honk - is this normal?

Discussion in 'Gen 3 Prius Main Forum' started by Joe-G, Apr 12, 2013.

  1. Joe-G

    Joe-G Member

    Joined:
    Feb 2, 2013
    243
    99
    0
    Location:
    Ft. Lauderdale, FL
    Vehicle:
    2010 Prius
    Model:
    IV
    I installed a Cadillac 4 horn system which gives a nice DM7 sound, but I notice that I can only give a short toot, no long blast of the horn.

    Is this normal Prius behavior - it will allow only a short toot, not a long blast? Did Toyota make the Prius polite by design, or is my 4 horn system overloading the relay?

    Appreciate if someone could let loose a long blast on their stock horn and see if it works or if it's a short toot.

    In case anyone is wondering, here is the difference in horns:

    Before:



    After (the phone mic doesn't do these babies justice...they are LOUD.


     
  2. css28

    css28 Senior Member

    Joined:
    Feb 27, 2012
    1,566
    442
    3
    Location:
    Suburban Detroit
    Vehicle:
    2011 Prius
    Model:
    Three
    No, that is not normal.
     
  3. BZzap!

    BZzap! Senior Member

    Joined:
    Jun 13, 2012
    1,607
    877
    0
    Vehicle:
    2012 Prius
    Model:
    Two
    It's probably overloading a breaker or relay. The horns are most likely drawing too many amps for the circuit.
     
  4. Joe-G

    Joe-G Member

    Joined:
    Feb 2, 2013
    243
    99
    0
    Location:
    Ft. Lauderdale, FL
    Vehicle:
    2010 Prius
    Model:
    IV
    Thanks folks. Has anyone actually tried to do a long honk?
     
  5. BZzap!

    BZzap! Senior Member

    Joined:
    Jun 13, 2012
    1,607
    877
    0
    Vehicle:
    2012 Prius
    Model:
    Two
    Try this. Hold the horn button down until it stops honking and keep the button depressed. If it's tripping a breaker the horn will eventually start honking again until the breaker trips again.
     
  6. Joe-G

    Joe-G Member

    Joined:
    Feb 2, 2013
    243
    99
    0
    Location:
    Ft. Lauderdale, FL
    Vehicle:
    2010 Prius
    Model:
    IV
    Good thought! I have already tried that. It won't. The horn beeps like you hear in the video, you can keep you hand on it all day if you like and it won't beep again until you remove your hand and press the horn again.

    I could run a separate relay, it's easy, but if the factory horn will only allow a polite beep then I'm wasting my time.

    If someone would be so kind to try and blast their horn for a long time and see if it works, I'd appreciate that.
     
  7. drysider

    drysider Active Member

    Joined:
    Apr 14, 2008
    823
    332
    1
    Location:
    Liberty Lake WA
    Vehicle:
    2012 Prius
    Model:
    Four
    I just tried it on my 2012/4 and it honks continually.......
     
  8. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

    Joined:
    Feb 14, 2010
    6,035
    3,854
    0
    Location:
    Rocky Mountains
    Vehicle:
    2006 Prius
    Model:
    Three
    The Prius horn will honk as long as it is depressed. If you tape it down and walk away it will still be blaring the next morning unless your battery dies.
     
  9. Sfcyclist

    Sfcyclist Senior Member

    Joined:
    Oct 23, 2012
    1,621
    375
    0
    Location:
    SF, CA
    Vehicle:
    2013 Prius
    Model:
    Persona
    It's a circuit and should provide 12v continuously. Hook up a test light or DVM to check. Or install your stock horn and see if it's solve the issue.

    My guess is it's your horns.

    I put in Fiamm's and I think still not loud enough on the Freeway. Not much of a "Freeway Blaster"! Might be time for airhorns!
     
  10. Joe-G

    Joe-G Member

    Joined:
    Feb 2, 2013
    243
    99
    0
    Location:
    Ft. Lauderdale, FL
    Vehicle:
    2010 Prius
    Model:
    IV
    Hmm...thanks for the info. Can't imagine my 2010 would be any different.

    I can run a separate relay, easy to do if I decide I need to. Actually the beeps you hear in the video have served me well. I do indeed love that Cadillac horn. Every time I use it everyone looks around as they can't believe that little Prius makes such a big sound. :LOL:
     
  11. phoenixgreg

    phoenixgreg Senior member

    Joined:
    Apr 7, 2010
    1,157
    288
    66
    Location:
    Phoenix
    Vehicle:
    2010 Prius
    Model:
    II
    How does the Cadillac horn work with your OEM security system? When you press the red fob button, do you get continuous pulses?
     
  12. Spaz

    Spaz Junior Member

    Joined:
    Nov 30, 2011
    82
    25
    0
    Location:
    New Jersey
    Vehicle:
    2011 Prius
    Model:
    Three
    My bet is the stock relay just doesn't have enough mojo to deal with those things. I know this is a terrible judge, but humor me and just look at the size difference...

    The real way to figure it out would be to look up the drawings for the relay and check out what the horns needs to operate

    Either way, a friend of mind used to have a tundra and when he did a similar upgrade he had to run a new line and new relay. I wanna say he had 2 horns and upgraded to 3 or 4, if he had to upgrade I'm sure a Prius would
     
  13. Joe-G

    Joe-G Member

    Joined:
    Feb 2, 2013
    243
    99
    0
    Location:
    Ft. Lauderdale, FL
    Vehicle:
    2010 Prius
    Model:
    IV
    Just tried it, works fine, beeps like you would expect.
     
  14. Koocuz

    Koocuz Junior Member

    Joined:
    May 21, 2013
    20
    0
    0
    Vehicle:
    2010 Prius
    Model:
    III
    Did you guys figure this out? I just installed my 4 caddy horns (as I have in previous vehicles and love them!) but same issue, they honk for about 1 sec and turn off until you hit the horn again. I custom made two harnesses, if I could just change a relay that would be awesome! I really dont want to tear the bumper off again, dang toyota! My old Mitsubishi mirage handled all 4 like a champ! Also on my 2010 there appears to be 3 spare +12v connectors, does anyone know the amperage of these? On the diagram one is labeled 7 (headlight washers) (not used) and the other two empty slots are not labeled..
     
  15. Joe-G

    Joe-G Member

    Joined:
    Feb 2, 2013
    243
    99
    0
    Location:
    Ft. Lauderdale, FL
    Vehicle:
    2010 Prius
    Model:
    IV
    I'm sure you will need to run a relay from the battery terminal in the fuse box. Easy to do. You can pull the top of the bumper loose to get at the connections I'm sure so you don't have to pull the whole thing off again.

    Personally after months now, I never need more than the 1 second beep. I might give a couple of them at times but I never need to blare on the horn continuously. As I think about it, that is always pretty rude. A few quick beeps are more civilized.
     
  16. David Beale

    David Beale Senior Member

    Joined:
    Jul 24, 2006
    5,963
    1,979
    0
    Location:
    Edmonton Alberta
    Vehicle:
    2012 Prius
    The "spare" connectors probably don't have metal in place. At least they didn't the last time I looked. Get a relay and wire the coil to the existing horn output and ground, then run the relay contacts from the +12V "boost point" to the horn wire you removed. I strongly recommend you install an in-line fuse from the "boost point", perhaps 10A.

    It sounds like you are overloading the existing "relay" (I think it's a solid state device). If you keep doing so it will probably fail. Or you -may- be able to replace it with a higher rated one, though I would be surprised if it would fit. They seem to grow in size with rating.

    You are modifying the car. If you don't fully understand how stop now before you destroy something expensive.
     
  17. Koocuz

    Koocuz Junior Member

    Joined:
    May 21, 2013
    20
    0
    0
    Vehicle:
    2010 Prius
    Model:
    III
    Thanks for the quick reply's where is this boost point?

    I attached a photo of the points I am referencing. I am just not sure what they can handle...

    I have modded many many cars in my past and my background is electrical.. I guess I am just used to beefy old mechanical relays..

    But yes, very good advice that I will take. I will put 2 of the 4 horns on its own source.

    Joe G, have you had any electrical problems since your mega horn upgrades?
     

    Attached Files:

  18. Koocuz

    Koocuz Junior Member

    Joined:
    May 21, 2013
    20
    0
    0
    Vehicle:
    2010 Prius
    Model:
    III
    Here are a couple photos of the work :)
    Also installed new fog lights and plan on using them for DRL's. Already bought some low wattage LED's. Couldnt stand the super ghetto covers toyota put on there.
    On the photo where the bumper is on the ground the LED is on the right, not too bright but good safety. Anyone put covers or plastic wrap on the glass lenses? I am worried they will get broken out in a hurry by rocks.
    Used the back of the grounding bolt on the front lower side (great spot for a couple more).
     

    Attached Files:

  19. Joe-G

    Joe-G Member

    Joined:
    Feb 2, 2013
    243
    99
    0
    Location:
    Ft. Lauderdale, FL
    Vehicle:
    2010 Prius
    Model:
    IV
    No problems and I toot the horns every day as I leave work.
     
  20. Joe-G

    Joe-G Member

    Joined:
    Feb 2, 2013
    243
    99
    0
    Location:
    Ft. Lauderdale, FL
    Vehicle:
    2010 Prius
    Model:
    IV
    I like the idea of drl's, my fogs are hid but not so useful, I rarely use them.

    My fog lights haven't cracked in about 10,000 miles. I did have one break on my Vette at about 60,000 miles or so.