Horn Resistance

[hi_volt]

I have the original dual trumpet horns in my new 47 Plymouth coupe.  I measured the resistance of each one between the screw terminal and ground and got completely different resistance readings.  The short horn measured about 3 ohms and the long one measured about 0.3 ohms.  It appears that the 3 ohm one should be about right, but the 0.3 ohm one seems low to me, as it would pull around 18 amperes at 6V.  Does anyone know what the resistance should read?  Thanks!

[Plymouthy Adams]

horns were tweaked by ear in the absence of an amp meter....you can tweak by amp draw if using a meter as a guide while still listening to the tone of the horn....the book shows 32-38 amps and that should be BOTH horns.  (later 111 wheel base cars only came with one horn per note in book)  Depending on the actual voltage available, battery or higher with car running and generator output, your resistance should be near the .3 ohm rating given the amperage stated as combined in the book.  Tone will be by trumpet length.  The book only states to set the horn by tone with the other horn disconnected.  I suspect that they figured the average car owner not owning an accurate amp meter.  If setting by meter...you will be near that 18 amps per horn.  The horn with the higher resistance is suspect....remove the cover, clean the points, verify good clean ground and open the contact....adjust to correct tone or amperage when tightening the adjuster..

[hi_volt]

Thanks Plymouthy!  It's interesting that the wiring going to the horns is not that heavy to carry up to 36 amps total.  I wasn't expecting the current to be that high.  I guess it doesn't need to carry it for that long unless someone leans on the horn.