The regular horn works fine, but when i unlock and lock all the doors, it sounds just like this little "blump" noise like you hear here. Are there two horns in our cars? Maybe a fuse or relay is messed up?
It wants to start a band! You have'im playing the drums already. lol.
There are fuses under the instrument panel left of the steering wheel. Also additional fuses with relays on the passenger side when you take off the sound insulator under there. Look in your owner'* manual incase it'* different for your model, I'm speaking for mine. Then you can visually inspect all the fuses. That'* all I can say becuase recently I inspected my fuses.
the fuses are under the back seat and in the engine bay, mine does the same thing, also if you just hit the horn a few too many times it starts to do the same thing, i haven't been able to get to the horns and apply straight power to them yet but i think it is just the horns that are worn out and need replacement