[Neckster]

DOT only requires one working horn. Freightliner Cent. the air horn is under the cab by the fuel tank on the drivers side. Most of the ones i've seen only have one air horn.

[Deus]

The air horn on the freightliner I drive really stinks. In fact when little kids do the little horn motion and I sound my air horn they point and laugh at me. :cry:

[Shawnee]

thats why i put train horns on my truck, little kids love them

[Blind Driver]

The rubber diaphram may have gone bad. Take the horn apart and replace with a similiar type of rubber. Easy and cheap 8)

Be sure you have proper airpressure. Could also be something wrong in the valve.

[mrpersons]

On a truck that age, the horn is probably just full of crap! Next time your out in the boonies, just blow on it for awhile!

If you have to replace it, they aren't very expensive. Last one I bought at a dealer was something like $42.