Classic/Antique Car Repair: Horn repair..., horn button, voltage drop

Question

1933 Packard horns. Thanks for helping.  I have a 1933 Packard Standard 8 and the horn does not work properly.  Everything appears to have been restored and it looks wonderful, but very little sound.  I have an excellent mechanic but he is puzzled as well.  Of course 6 volt.  Any help greatly appreciated.  Russ

Answer
Very pretty car! Well, check the voltage at the horn when the horn button is activated.It should be near battery voltage. If the voltage is low it indicates a voltage drop in the system. The most common is the relay. The points in the relay get burned and then act a resistor in the system. If the voltage is near battery, within .5 volts, then the problem is inside the horns themselves.