Skip to main content ↑ ↓
Topic: How to stop the air horn (Read 920 times) previous topic - next topic

How to stop the air horn

So I was testing my air step yesterday. My kids was in the bus, they probably pushed the button on the wheel. The air horn went off. And it can't be stopped. It keeps emitting sound until the air pressure is low.

But then the bus can't build air pressure properly. The air horn is leaking air so that the pressure can't be over 65 psi.

I think the solenoid is stuck. My question is where is this solenoid which controls the air horn?

1991 GV

Thanks!
1991 Grand Villa U300

Re: How to stop the air horn

Reply #1 –
Lift the dash -it is directly behind the wheel . 2 hoses, 2 wires. Disconnect the green wire. (ground)
 Pry off the horn button and fix the itty bitty wire. Imade a short extension  so that I could put it back together. 

Re: How to stop the air horn

Reply #2 –
Thanks for the quick reply.

I will give it a try.



1991 Grand Villa U300

Re: How to stop the air horn

Reply #3 –
Thread linked below has some photos of the horn button and how it comes apart.

Grand Villa Steering Wheel Removal
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: How to stop the air horn

Reply #4 –
Or it could be a bad/stuck solenoid.  I would start at the solenoid/air valve.  disconnect power and see if it still leaks.

Can't blame the horn button/wiring of it still blows with wires disconnected!
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: How to stop the air horn

Reply #5 –
I finally got chance to take a look at the air horn issue. The horn still went off as soon as the air pressure goes above 30 PSI regardless of the horn button. So it is very annoying. And due to the air horn leak, air pressure can not be build up to 65 PSI.

I followed @Chuck & Jeannie post to get the horn button out. After some testing the horn button works fine. So the control valve has to be the cause. After fixing so many small things, I am not in panic mode any more. As @stump said, most of the issue are caused by some valve or solenoid. Just find the broken one and fix or replace it.

The next question is where is this solenoid. @Protech Racing mentioned "life the dash it is directly behind the wheel". I wasn't sure what that means. So I dig up the schematics for the air system



According to the diagram, the solenoid is right beside the air pressure gauge. BTW, what does the 48 in the square mean?

Looking behind the dash, there is a solenoid like thing right beside the air pressure gauge.


I tested using multimeter, when the horn button is pushed, I got 13v on the solenoid. So it has to be this one.

Now I know what @Protech Racing is talking about "directly behind the wheel ". A picture is worth than thousands of words!

After located the solenoid, it seems like very hard to replace if the parts can be found. But I remember when I was replacing the engine air compressor governor. @stump  asked me to use hammer to tap the governor to see if it will loose up. It didn't work on the compressor governor, but the logic behind it is good. Just some little tap to help the stuck valve back to it's position. So I use the plastic handle of a screw driver to tap the solenoid for few good minutes.

That worked! ^.^d  ^.^d

Thanks for you guys reply. This forum is the best!






1991 Grand Villa U300

Re: How to stop the air horn

Reply #6 –
Quote from: Running Odometer –
BTW, what does the 48 in the square mean?
Most of the major air lines are numbered.  Look for a white paper tag [48] on the plastic air line going from the solenoid to the horns.

A "stuck" solenoid can be caused by lack of use (Use It or Lose It), or by foreign debris in the air lines.

Service your air dryer regularly to avoid air system problems.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: How to stop the air horn

Reply #7 –
Ah, that make sense.
Thanks Chuck!
Now I know the air line is also numbered.

The air horn solenoid is probably not used for a good 15 years. 

I will need to learn how to service air dryer.

1991 Grand Villa U300
 

Re: How to stop the air horn

Reply #8 –
Quote from: Running Odometer –
I will need to learn how to service air dryer.
See subject "Air Dryer" on pages linked below:

Air Dryer [ForeForums Foretravel Motorcoach Wiki]

Foretravel Motorhome technical help and information links
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"