Need help with strange horn problem

[ScottH]

Problem is I cant get it to work, it is a 72 c10 with a grant wheel. When I press on the horn button the horn relay clicks like it should. If I use a circuit tester on the horn wire it lights up when I press the horn button. I have tried 4 other horns plus a brand new one and none work. Cleaned all grounds, even tried hooking each horn directly to the battery and none worked. Also replaced the horn relay with a new one, same results.

If anyone has any suggestions on what to do next I would appreciate it.

Thanks
Scott

[Stocker]

Originally Posted by ScottH

Problem is I cant get it to work, it is a 72 c10 with a grant wheel. When I press on the horn button the horn relay clicks like it should.

circuit from horn button is good

If I use a circuit tester on the horn wire it lights up when I press the horn button.

horn relay is good

I have tried 4 other horns plus a brand new one and none work. Cleaned all grounds, even tried hooking each horn directly to the battery and none worked.

Hard to believe 5 bad horns, but if you connect it directly across a good battery and it doesn't work, it's gotta be a bad horn. (make sure your battery is good)

If not for that last test, I would suggest your core support (which the horns mount to) is not properly grounded.

[Andy4639]

Horn hooked straight to the battery.

Wire hook up to positive of battery and ground the horn itself and it doesn't work. 5 of them that's unherd of.

[ScottH]

I find it hard not one of the horns will work, driving me nuts.
I think I have a couple more horns around here, will try a couple more.

thanks for everyones input.

[ole dollor]

it is hard to believe that 5 horns would be bad.....but that is what is sounds like, are you getting a full 12 volts out of your battery and at the horn wire?...

[domeier]

Welcome to Grant-aholics Anonymous, the place people come for sympathy and support regarding Grant horn problems. We usually start the meeting like this:

"Hi, my name is Bob, and my horn doesn't work."

You're one of the lucky ones; Your wheel button works. You are one in a million!

[LockDoc]

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Make sure where you are grounding the horn is shiny metal. I usually take a file and make a shiny spot on the corner of the bracket. You might try rapping on the horn with a small hammer handle or screwdriver handle in case the points are stuck a little bit.

LockDoc

[Stocker]

Spraying WD-40 into a non-working horn sometimes gets it to work..... or so I've been told.

[cdowns]

the stud that the horn is mounted is your main grounding point of the horn

[ScottH]

Ok, I must be doing something wrong, just dont know what.

I took 6 horns and wired them directly to another good battery.
I went directly from ground to mounting bracket, and hot to wire terminal.
I used a test light in the positive connection and each time it would light up so I know I am getting a completed circuit.
NONE of the horns worked.

WHAT AM I MISSING???

[cdowns]

take horn off mounting bracket wrap ground wire around the stud that the horn mounts to go to neg battery terminal// postive terminal hook to horn spade unit

[Stocker]

Originally Posted by ScottH

I used a test light in the positive connection and each time it would light up so I know I am getting a completed circuit.

Maybe I'm reading this wrong -- if your test light is in series with the positive side of your circuit, then yes, it will light up.... but probably won't flow enough current to operate the horn. The positive lead needs to go directly to the terminal on the horn. Then check the connection with the test light separately (that is, in parallel).

[hayhauler71]

Originally Posted by Stocker

Maybe I'm reading this wrong -- if your test light is in series with the positive side of your circuit, then yes, it will light up.... but probably won't flow enough current to operate the horn. The positive lead needs to go directly to the terminal on the horn. Then check the connection with the test light separately (that is, in parallel).

What he said you will never pull enough currant through the filament of the test light bulb and have the horn work

[Andy4639]

I stated this in post #3. Hook horn straight to battery and ground. Didn't say anything about a test light though. That would do it though not enough amps passing the bulb to sound the horns.

[Stocker]

Scott, think of current flowing through a wire as being similar to water flowing through a hose. Whatever job you want done (like blowing a horn) will require a certain volume of current flowing through the circuit.

In order for the horn to work, it takes quite a bit of current. If the horn ran on water (instead of electricity), let's say it takes the volume that a garden hose can supply. If you insert a test light into the path of the flow, it's like inserting a straw inline with the garden hose. The flow becomes so restricted that the horn cannot operate.

Hope this illustration helps and doesn't just confuse things more!

[ScottH]

thanks guys....will retest without test light