[David R.]

I would echo Big Hammer. I would check all your electrical connections; including ground path. Rule for electrical connections is clean and tight. Paint is an insulator. Any poor connection adds resistance which translates to higher current (measured as amperes) draw. Clean horn motor commutator and oil bearings. Make sure bearings are good and not dragging. I picked up an old horn recently. It worked ok as found, but I cleaned commutator with fine sandpaper and a wooden stick like service manual describes and after oiling, was amazed how much clearer and cleaner the tone was.