^^ This is odd?
Which bulb are u using? original stanley biulb is a bit expensive, never use 15,20Rs wala bulb... and look for the bulb holder. And do see an expert electrician next time... Junoon's wiring and electronics aren't upto the mark!
To keep it "original" I beared with a troubling horn for about 3 years! and recently I got an excellent job done by my electrician.. he fitted a car's relay before the horn, now the horn is full loud and never troubles!
Previously horn was 80% of the time not working at its full capacity.. as if the battery is discharged or weak!
So accept this fact and get the electronics examined, dont be in love with its "Originality" and newness... factory fitted stuff is crap