Anybody heard of this? 2002 silverado, horns have always worked fine. Blow every time I lock it like it should until a couple days ago. Blew the horn and sounded like only the high tone horn was working. FINALLY found them and when you blow the horn both work but just a high note! Is there some kind of solenoid or relay that controls the sound?? Usually just a high and low set of horns but both are working!