? are you trying to spray into the trumpet opening? The only thing that would do is possibly help dislodge dirt-etc.. The ""workings"" of the horn are sealed up inside the motor housing. There is a coil in there and a set of braker points. When the coil is enerjized the magnetic field draws a plunger (mobil nukleus) and that plunger opens the points and that drops out the "magnetic" field and repets.... as long as you hold the power to the horn. The "star wheel screw" adjusts the distance the points are from the "mobil nukleus". You should have continuity thru the horn. The "housing" is ground on most single terminal horns. ohms should be about 2to5 omhs.