Horn blows the fuse

[Austin86250]

updated for better format

*Horn fuse blows when I press the horn will never blow if I don’t press the horn

* fuse still blows even when the horn relay is disconnected

* no 12v to yellow/ LB wire in horn relay connector

* no continuity to yellow/ LG wire on the horn relay connector and either of the horn connectors

* there is continuity between the DARK BLUE wire on the horn relay connector and the spade on the steering wheel where the blue wire from horn pad connects

* the DARK BLUE horn wire doesn’t have continuity to any other pins on the turn signal switch connector

* this problem has carried over from 3 columns, 2 steering wheels, 2 horn pads, and multiple turn signal switches (these where not replaced for horn reasons)

* the horn did work at one time in my ownership of the truck but it was years ago

* the horn does work when 12v is directly applied


It is to my understanding that the dark blue wire / signal to relay from horn pad works off a ground and what the horn switch is doing is grounding the dark blue wire which activates the relay
When the relay is activated it sends the 12v coming from the fuse box to the horns

 

[ihc1470]

The horn button is at ground potential when depressed. Allows the coil in the relay to pull the arm over making contact with I believe pin 6 sending power onto the horns. I suspect you have a grounded wire between the relay and the horns. Disconnect the wires at the horn and push the button I suspect you will still blow the fuse.

 

[Austin86250]

The horn button is at ground potential when depressed. Allows the coil in the relay to pull the arm over making contact with I believe pin 6 sending power onto the horns. I suspect you have a grounded wire between the relay and the horns. Disconnect the wires at the horn and push the button I suspect you will still blow the fuse.

The wires to the horns are disconnected and it blows yes,

Also still blows when the relay is disconnected

Both circled things are grounds on the horn, I found that off but it works when hook up 12v

I am not getting 12v to y/Lb on the connector

Nor am I getting continuity to either of the horn connectors from the y/lg on the relay connector

I’m thinking I’m going to have to just run my own wiring for 12v and output

 

[ihc1470]

I do not see how it can blow the fuse if the relay is disconnected as there is no path to the horn switch. If you trace the wires on the diagram you see that yellow light blue is the power from the fuse that goes to lighter and horn relay. It has to go through the relay coil coming out on pin 1 the dark blue wire which then goes to the horn button, which is a ground. When you push the button to blow the horn current flow through the relay pulls the switch arm to close which in turn sends power to the horns. Silly question but are you sure you are looking at the correct relay?

 

[Austin86250]

I do not see how it can blow the fuse if the relay is disconnected as there is no path to the horn switch. If you trace the wires on the diagram you see that yellow light blue is the power from the fuse that goes to lighter and horn relay. It has to go through the relay coil coming out on pin 1 the dark blue wire which then goes to the horn button, which is a ground. When you push the button to blow the horn current flow through the relay pulls the switch arm to close which in turn sends power to the horns. Silly question but are you sure you are looking at the correct relay?

I agree with the I don’t see how it could aswell genuinly lost

I also thought if I had the wrong relay aswell but it was mounted to the back of the speed control amplifier as described, the colors of the wires match, and the blue wire has continuity correctly

I’ll double quadruple check I have the right relay becuase that’s why my brain went to first aswell but I’m pretty confident

Confusing picture but what’s circled in white is the speed control amplifier

And in orange is what I believe to be the horn relay I pulled it off the speed control amplifier and you can see the wire colors are matching

 

[Old Goat]

Horn blows fuse

Facebook has let me down time to go to y’all I’ve got a 86 f250 cruise when I hit the horn the horn/ cigarette lighter fuse blows Manually suppling 12v to horns they work Cigarettes lighter works while fuse isn’t blown Swapped relay with a china orilley s ones didn’t look exactly correct but...

www.oilburners.net

Saw your other thread in the below Similar Threads.


Goat

 

[ihc1470]

You might try using a short circuit detector and see what it tells you.https://www.ebay.com/itm/267376954989?_skw=12+volt+short+circuit+detector&itmmeta=01K8F70TE41TRD98SGHCBWXJDN&hash=item3e40e88e6d:g:YuIAAeSwzTloqQQy&itmprp=enc%3AAQAKAAAA4FkggFvd1GGDu0w3yXCmi1cMUCJBd9cYwveYZyK%2FCRos%2FbQrQwyc1aOKrjsAR%2FBGU0G4CZeqvLURFU8Ca9%2FsmHBDlF5sOPjcYRtuPbQJuJg1X3SpQfz39E7WDRohzSyebGp417LuPIiB7Hzxvqx%2Fl2zbkf5X6FKwRzk2upCK603T6dt6%2FVvFAkYP%2FAe69O4Nt608QTMaQe07WNYu3l0JuXxOoIWqnRfiyJ0eJDafB5UJSQEqmc%2FekGlHZAGTgVG8zHlQdri9EdgXnZfmkgPzxfTanyaMHiyuEh0czwMfFVbi%7Ctkp%3ABk9SR56ng-fDZg

I have used one for several years. The only thing I do not like is it takes a bit for the circuit breaker to reset. A turn signal flasher would serve the same and should cycle faster. I was going to make one and install a buzzer so you could also hear it as once in while if you disturbe the harness the short (actually grounded circuit) will pull away from the ground and go back to working. You may not notice it right away if not paying close attention to the needle swing but you would hear it not making a noise.

 

[Austin86250]

The solution to this is a bit embarrassing

So on the cruise truck there is a speed control amplifier and that is what the horn relay goes off of
As the horn relay is specific to cruise trucks

As on non cruise trucks 12v goes to one spade on the wheel horn pad sends that back down and to the horns easy

Cruise trucks does the ground to trigger a relay

Anyways relay is apart of cruise which the cruise box gets wiring from teeing into the turn signal switch wiring identical plugs

What I did years ago was connect the turn signal switch strait to the truck instead of though the cruise control box

So that was half cruise and half non cruise wiring

Making when I press the horn it connected the 12v to the ground of the cruise horn pad, snapping the fuse

After connecting it properly (20 seconds) horn works great
So yea I spent “days ripping my hair out” and years of not having a horn of a simple connector swap

But thank you to Tony’s auto care who helped me over the phone

 

[ihc1470]

Glad you got it worked out.