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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: gto109 on August 23, 2012, 05:58:15 pm

Title: Fuse pops when I press the horn
Post by: gto109 on August 23, 2012, 05:58:15 pm
I am thinking I need a new horn every time I press it, it pops the fuse.  Anyone else know of what else it could be?
Title: Re: Fuse pops when I press the horn
Post by: 78 Chevyrado on August 23, 2012, 06:09:24 pm
unplug the horn itself and then hit the horn button.  that should rule out if it's the wiring or not. 
Title: Re: Fuse pops when I press the horn
Post by: DnStClr on August 30, 2012, 04:51:30 pm
There's a short to ground somewhere. did you do what Kenny said?
Title: Re: Fuse pops when I press the horn
Post by: Irish_Alley on August 30, 2012, 09:47:48 pm
you could stop using the horn and use a finger or two, there is that bumper stick that says "horn broke watch for finger"r something to that effect, this would be perfect for you
Title: Re: Fuse pops when I press the horn
Post by: gto109 on August 31, 2012, 04:41:29 am
I finally had enough time to get to it and disconnect the horn and the fuse didn't blow after I did that.  It doned on me after I wrote this that I hooked the horn back up a few months ago and thats when the radio and dome light stoped working.  Now with the horn disconnected the radio and dome light work fine.  Now I know why the p/o had them unhooked and put a cheep air horn in it. 
Title: Re: Fuse pops when I press the horn
Post by: DnStClr on September 03, 2012, 05:23:37 pm
All those items -horn, dome light, radio, and cig. lighter, are  on the same circuit, so that accounts for the others working when the horn is disconnected. They all get their hot signal from a relay, and I think it's the one up under the dash behind the brake pedal. It's  hard to get to if you're a  big guy because it's way up there.. anyway, it sounds like the relay is ok.  With the horn wire off the horn and making sure the ground is good at the horn, I'd put a jumper wire from the battery B+ to the horn to see if it works.
 On edit, I just remembered that you may have 2 horns, like mine. The drivers side horn has 2 wires, a hot and a ground (black wire) while the passenger side just has the hot wire. The wiring  terminals can be accessed thru the grill to disconnect them. While testing, each would have to be grounded separately.
Title: Re: Fuse pops when I press the horn
Post by: gto109 on September 04, 2012, 04:31:43 am
I am going to have to look and find the ground for them.  I have the 2 horn set up as well.  Although there is no wires going to the right/pass side horn.  Where do I put the jumper wire at on the horn to check it?
Title: Re: Fuse pops when I press the horn
Post by: DnStClr on September 04, 2012, 10:58:52 am
Two jumpers actually. One goes from the case of the horn to ground. The 2nd jumper goes from the B+ terminal (hot side) of the battery to the horn elect. connector. You might have to take the grill out to access the elect. connector. It's on the back right side of the horn. (Wouldn't ya know it..)
Title: Re: Fuse pops when I press the horn
Post by: DnStClr on September 04, 2012, 11:19:34 am
Here's a diagram of a typical horn system. notice how the switch (horn button) is used only to control ( open or close) the relay. That's all it does. The relay gets 12 volts from another source- the fused circuit-to send out to the horns and other accessories.
http://www.ado13.com/techs/relay.htm (http://www.ado13.com/techs/relay.htm)
Title: Re: Fuse pops when I press the horn
Post by: 78 Chevyrado on September 04, 2012, 08:43:40 pm
you could stop using the horn and use a finger or two, there is that bumper stick that says "horn broke watch for finger"r something to that effect, this would be perfect for you

I like it! :)


As far as your problem, sounds like the horn is toast.  I'd go get a junkyard set and see if that helps.  I like to hunt for 70s-80s caddys for mine.  if you do put all four on there add a relay.

On these trucks, the horn gets a 12v+ wire and the bolt holding the horn on the truck is the ground. 
Title: Re: Fuse pops when I press the horn
Post by: gto109 on September 05, 2012, 04:34:13 am
I know where there is a 90 burban in a boneyard that I will test the horns in on Monday or Tuesday.  I do not know of any 70-80s caddy's in the boneyards around here anymore most of the stuff here is mid 90s and up.  I have a hard time finding stuff for Kim's 86 Trans Am in the boneyards as well.
Title: Re: Fuse pops when I press the horn
Post by: bake315 on September 27, 2012, 10:53:14 am
I like to hunt for 70s-80s caddys for mine.

Awesome idea.  I think I'm gonna do that on mine.  Caddy horns sound cool!