Air horn sticks on.

[tmpugel]

I recently bought a 1986 AM General M925 A1, 5 ton 6x6 Catrgo truck.
My first problem is the air horn sticks on. I replaced the switch at the steering wheel but that did not correct it. Is the selenoid at the horn or attached to the firewall.
I'm new to this. I need some advice.
Thanks
Tom Pugel

 

[patracy]

Moved to 5 ton forum. The lead from the button on the wheel to the solenoid should be the ground lead. Might need to check for a short.

 

[Digger09]

Clean out where the actual horns thread in. Sometimes junk gets built up in there. Some type of lubricant usually does the trick.

 

[The HUlk]

Is the selenoid at the horn or attached to the firewall.
I'm new to this. I need some advice.
Thanks
Tom Pugel

The solenoid valve should be on the front of the horn and have two wires connected to it. If removing the wires does not deactivate the horn then remove the solenoid valve from the horn. If air is comming through the solenoid valve with no wires connected then the solenoid valve is likely stuck open. A little oil may help it.

 

[juanprado]

There is a diode in the wiring coming off the horn to the ground if I remember correctly. It is a known failure. Another member here posted the number and easy to find off epay, cut out and replace. Do a search......

 

[rsbillings]

Horn will not stop on my 1991 M923a2

I have a 1991 M923A2 with 18,000 miles on it. About 2 weeks ago as I was driving to the gas station the horn started to blown on it's own. I had to open the hood and disconnect one of the two wires on the solenoid value to stop the horn. I'm stumped and need some direction to systematically check everything that operates the horn in a logical order/manner. Any help will be greatly appreciated.

 

[acolesurf]

I have a 1991 M923A2 with 18,000 miles on it. About 2 weeks ago as I was driving to the gas station the horn started to blown on it's own. I had to open the hood and disconnect one of the two wires on the solenoid value to stop the horn. I'm stumped and need some direction to systematically check everything that operates the horn in a logical order/manner. Any help will be greatly appreciated.

It’s the diode going to ground. Unplug it and it should work normally after that.


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[acolesurf]

If it doesn’t, it’s the solenoid.


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[rsbillings]

Thank you so much for the info; my online TM does not have a wiring diagram for the air horn. I'm not sure where I find the diode/ground to do the disconnect. Any help here will again be appreciated

 

[simp5782]

Thank you so much for the info; my online TM does not have a wiring diagram for the air horn. I'm not sure where I find the diode/ground to do the disconnect. Any help here will again be appreciated

download the P2P program for a wiring diagram rather than the TM. The diode is the wire with a enlarged section on the wire. that is your diode. It is near the horn on that end of the harness that comes across the firewall.

 

[tmpugel]

Air horn sticks

I have a 1991 M923A2 with 18,000 miles on it. About 2 weeks ago as I was driving to the gas station the horn started to blown on it's own. I had to open the hood and disconnect one of the two wires on the solenoid value to stop the horn. I'm stumped and need some direction to systematically check everything that operates the horn in a logical order/manner. Any help will be greatly appreciated.

My problem was caused by water in the connections at the bottom of steering column. I opened the cover and temporarily bypassed the connections and is ok.