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| | | | Joined: Jun 2014 Posts: 106 Shop Shark | | Shop Shark Joined: Jun 2014 Posts: 106 | I have two different length horns in the '37 1/2T - Town and Country horns? We have applied 6V and get a single "thump".
Is there any wiring diagrams our instructions out there for rebuilding these horns? | | | | | Joined: Aug 2005 Posts: 6,378 Ex Hall Monitor | | Ex Hall Monitor Joined: Aug 2005 Posts: 6,378 | Before '39 they were simply called accessory horns. Try cleaning the contacts. I'm no expert but what happens is when you complete the circuit by pressing the horn button an electromagnet is powered up with pulls the diaphragm in one direction. At full travel a 'nub' on the diaphragm makes contact with a spot that breaks the circuit allowing the diaphragm to go the other way. This happen really fast and the back & forth is what makes the honk. If you're getting a single thump the nub isn't making good enough contact so the diaphragm is being held to one side instead of vibrating back and forth.
Save a life, adopt a senior shelter pet.
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| | | | | Joined: Jun 2014 Posts: 106 Shop Shark | | Shop Shark Joined: Jun 2014 Posts: 106 | Hi Tiny,
Thank you fort he explanation. This is what I thought when I had everything open.
The contacts on this horn appear to be in the "black box" mounted to the bracket. I thought we had cleaned them. I will pull them apart and do some resistance checking...
| | | | | Joined: Aug 2005 Posts: 6,378 Ex Hall Monitor | | Ex Hall Monitor Joined: Aug 2005 Posts: 6,378 | There's a dome on the back of the horn with a single screw in the center. Remove the screw & dome to expose the workings.
Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.
| | | | | Joined: Mar 2004 Posts: 6,236 'Bolter | | 'Bolter Joined: Mar 2004 Posts: 6,236 | The "black box" on the mounting bracket is the horn relay. It's needed to control the heavy current needed to sound the horns. The horn button triggers the relay. As Tiny says, the vibrating contacts are under the cover on the back of each horn. Mike B 
Last edited by Mike B; 08/25/2015 3:48 AM.
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