Jocko_51_B3B Posted November 11, 2015 Report Share Posted November 11, 2015 (edited) Does polarity matter when it comes to hooking up these old horns? This horn works regardless of which way I momentarily connect 6V to it but I don't want to damage it by connecting it incorrectly...The electrical schematic in my 1951 B3B Driver's Manual shows a wire coming from the negative battery terminal going to one horn post and chassis ground coming through the horn button. I'm doing an original frame off restoration and I'm keeping the positive ground system. The horns on the left were on my B3B when I bought it. They were made by the Sparton Company. I don't see these horns in my B3B schematic. Anyone familiar with them? Are they aftermarket? The ones on the right I picked up for $20 at a car show swap meet because they looked similar to the Sparton horns but they are stamped Autolite. The guy who sold them to me said they came off a mid-50s Imperial. Wondering if polarity is important to these horns as well. I just think that investigating the details about these parts is kind of interesting from a historical perspective as well as a mechanical / electrical one. Edited November 11, 2015 by glenn777 Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted November 11, 2015 Report Share Posted November 11, 2015 no..the relay or the horns are not conscious of polarity..only of a completed circuit..your horn ring/button will take the relay to ground.....no power runs through this light duty contact.. Quote Link to comment Share on other sites More sharing options...
ggdad1951 Posted November 11, 2015 Report Share Posted November 11, 2015 Even if you don't haveven a relay it doesn't matter Quote Link to comment Share on other sites More sharing options...
JBNeal Posted November 11, 2015 Report Share Posted November 11, 2015 the original wiring diagram shows voltage connected to the horn, with the horn button acting as the ground contact switch and no relay involved. If you follow the path to ground from the horn button, continuity has to pass through at least one bearing, the steering gearbox case, the frame, and several bolt connections before getting to the transmission case where the battery was originally grounded. Over time, corrosion can increase the impedance at these locations, decreasing horn effectiveness, especially in the original 6V setup. I put together a modified wiring diagram that shows a separate ground wire that would have to be installed to a modified horn button that could bypass all of those connections with a clear path to ground. At some point I may get back to finalizing this horn button modification, but until then it's just pie in the sky Quote Link to comment Share on other sites More sharing options...
Jocko_51_B3B Posted November 12, 2015 Author Report Share Posted November 12, 2015 (edited) All good information especially about the many failure points involving the path to ground. When I finally start reassembling I want to pay special attention to preventing electrical glitches from bad wiring. I wonder why my '51 B3B Driver's Manual circuit diagram omits a horn relay. I momentarily touched the contacts of my "fog horn" (the long black one that looks like a megaphone) with a 6V manual battery charger and the horn was quite loud. It must draw a pretty good current. I wonder if measuring the horn's resistance and using 6V/ohms = current would be a valid way of determining how much current the horn draws and, from that, the necessity of having a horn relay in the circuit. By the way, is anyone familiar with the horns that kind of look like sea shells by the way the sound path is all wound in a spiral? Edited November 12, 2015 by glenn777 1 Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted November 12, 2015 Report Share Posted November 12, 2015 later model horns..built for compact size and easier placing in areas out of sight and out of way for other accessories as the cars got more and more things added at the factory... if were me..I would add the relay...you can place an ammeter inline with the battery and the horn and make a reading...but a standard 40A relay will be more than sufficient...twin horns of the ear draws some 32 to 38 amps combined.. Quote Link to comment Share on other sites More sharing options...
andrewj7 Posted November 16, 2015 Report Share Posted November 16, 2015 I've just found that my truck has two extra horns behind the front grill. They look just like the B3B ones above. I also have the standard long horn B1B too. Of course neither are wired, have relays and the horn button is missing from behind the cap on the steering wheel. Something else to add to the list to get working. If anyone has sources for the button it would be much appreciated. Quote Link to comment Share on other sites More sharing options...
48Dodger Posted November 18, 2015 Report Share Posted November 18, 2015 The sea shell horns you have there are the like the ones you find in late 60's to late 70's vehicles. Not sure of the exact "when" to "when" 48D Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted November 18, 2015 Report Share Posted November 18, 2015 If I recall I found my seashell horns on the bay several years back. I believe they are aftermarket. Due to my Desoto engine and having to move the radiator forward I no longer had room for the trumpets. Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted November 18, 2015 Report Share Posted November 18, 2015 I got a pair of later model hooters on my coupe..they barely out of their teens in age.. Quote Link to comment Share on other sites More sharing options...
MBF Posted November 19, 2015 Report Share Posted November 19, 2015 I can't tell from your pictures of the newer styled horn how many connections are on them, but I don't see any insulating type materials on them. I'm going to assume that they ground through their mounting brackets and there is just a single post to connect switched positive feed to. The original Dodge horns are insulated by the use of the phenolic washers on the mounting bracket and have two connections. There is permanent negative feed to them whenever the key is on (remember these were originally positive ground), and the positive or ground completes the circuit when the horn button is pushed. You'll have to change your wiring if you want to use the newer styled horn. Your steering column isn't insulated from the grounding circuit so care will be needed to not cause a direct short. Mike Quote Link to comment Share on other sites More sharing options...
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