Air horn woes

[tbar123]

When the battery is turned off the horns stop. I have taken all four screws loose on the horn switch box(1 at a time) to see if those were grounding. No change every time the battery is turned on the horns blow!

 

[Cape Coastie]

Sorry tbar, I misunderstood. Thought they were sounding anytime the pressure was above 60 even with the batteries off. You got me on this one. Good luck. But I think you are looking in the right direction with chasing the grounds.

 

[tbar123]

Your good Cape, I do appreciate any advice, because I'm completely stumped on this. Here is a few pics of the wires I jumped.I suppose pic 2 is the diode. Pic 1 is where 25 and 25A split.

 

[The HUlk]

Remove wire 25A from where it connects to GND. Does that stop the horn from sounding?

 

[tbar123]

No it does not, I tried that when I was jumping the wire. When the horns started to blow I disconnected the ground and the horns continued to blow.

 

[The HUlk]

No it does not, I tried that when I was jumping the wire. When the horns started to blow I disconnected the ground and the horns continued to blow.

Did you have the GND disconnected without the jumper wire in place?

 

[tbar123]

I'm not sure, 25 was connected to the solenoid,and 25A ground to the firewall was disconnected.

 

[The HUlk]

I'm not sure, 25 was connected to the solenoid,and 25A ground to the firewall was disconnected.

A jumper across the diode will cause the horn to sound. I would remove any jumper and disconnect 25A at it's ground point. Then see if that stops the horn from sounding.

 

[tbar123]

I'll try that after Mom gets out of bed! I think she'd kill me if I started blaring those horns when she's in bed!

 

[The HUlk]

I'll try that after Mom gets out of bed! I think she'd kill me if I started blaring those horns when she's in bed!

Lol. Good idea, best of luck.

 

[doghead]

Air horn woes!

I have no schematics to look at and I'm on my phone but I keep thinking the horn button in the steering column simply grounds to activate the horn isn't the power on whenever the ignition switch is on so where are you disconnecting the ground

 

[tbar123]

Doghead, I've removed every ground (1 at a time) except 25 the wire to the solenoid and the horn continues to blow.The only wire that will stop the horn is disconnecting 25 from the horn switch located at the bottom of the steering column.

 

[The HUlk]

I have no schematics to look at and I'm on my phone but I keep thinking the horn button in the steering column simply grounds to activate the horn isn't the power on whenever the ignition switch is on so where are you disconnecting the ground

Power ia always supplied to the solenoid from wire 26 as you mentioned. GND is supplied to the solenoid through wire 25 when the horn switch is pressed as you mentioned. Wire 25A is tied to GND, has a reversed polarity diode, and connects to wire 25. The reverse polarity diode should not allow GND to reach the solenoid which would cause the horns to sound. However diodes sometimes short internally when they go bad. The reason for removing wire 25A from GND is to be sure a shorted diode is not causing the horns to sound.

 

[doghead]

Air horn woes!

So if he tried it with the diode disconnected and it still went off, it sounds like the problem is in the wire going through the steering column. which could be simply tested with an ohm meter.

 

[The HUlk]

The only wire that will stop the horn is disconnecting 25 from the horn switch located at the bottom of the steering column.

If this is the case then the horn switch is providing GND to the solenoid when not being pressed. Figure out why this is happening or get a switch that doesn't do this.

 

[doghead]

I would remove the horn button and disconnect the wire at the bottom of the steering column and test with the continuity test took around to see if that wires shorted it most likely is

 

[tbar123]

I checked both steering columns for continuity and both check out to be good.

 

[The HUlk]

So if he tried it with the diode disconnected and it still went off, it sounds like the problem is in the wire going through the steering column. which could be simply tested with an ohm meter.

Correct, however he says wasnt sure whether or not a jumper was in place which would cause the horns to sound. That is what I wanted him to confirm. Now that he has explained removing GND from the horn switch stops the horns, it's obvious there is contact through the switch when there shouldn't be.

 

[tbar123]

THe second test I plan to run today is take the box off of the steering column horn switch and then see if the horn still blows. If it does then the cover isn't making contact, if it does fix it then it is making contact and I'll have to fix that.

 

[tbar123]

I also put the old horn switch on the new column and I still have the same problem.