Hello everyone, I've searched all topics about horns but couldn't find an answer. I've recently bought a restored 6v truck horn from ebay but I'm not sure how to wire it. Years ago I restored a pair of Chevrolet 51' horns which had only one cable going out and the housing was acting as ground. Now, the truck horn I bought has two possible connections, so my question is which one goes where and how can I know? Is one the ground and the other one goes to the relay? I've found a wiring diagram but I want to be 100% sure first because I don't want to burn it!. My truck has a 12v system but from what I've read as long as I don't use it for long periods of time it should be fine. Thanks! Damian.
Horn Basics ALL two connection horns work the same way , one terminal is power , the other is ground . You can apply power to it and have a relay ground it when the horn button is pushed or the other way 'round , the horn doesn't much care .
Wire connection! I bought one like this a while ago installed it and wired it up like said here . It works just fine! Martinius.
The horn itself is always hooked up hot to the battery. The horn button acts as the ground & completes the circuit when the button is pressed. 12 volts through a 6 volt horn is a sure way to fry the contact points inside the horn.... no matter how long you lay on the horn button.... every time 12 volts go through the points it IS burning them & your restored horn will be short lived. Do yourself a favor & install a 12V to 6V reducer to protect the horn contacts & the relay switch. http://www.ebay.com/itm/Voltage-Red...Parts_Accessories&hash=item33886c62a8&vxp=mtr
Horn Amps question Joe Do you know how much amps usage the classic 6 volts horn have ? The reducer shown in your URL have a max of 4 amps it says in the manual. Different assesoiry to connect up to 12 amps! I dont get this really ? Martinius.
The reducer that this URL points to is 4 amps max. The horn uses more than that. Use of this reducer with a 6 volt horn on a 12 volt system will let the magic smoke out of the reducer. Getting the smoke back in is very hard to do.
6v hornies Ive been using 6v horns on my 12v trucks since 1974. All are still working just fine! Of course, I don't drive down the road laying on the horn button. Only used when needed.
Horn spesifications. 1950 Chevy horn spesifications ; http://chevy.oldcarmanualproject.com/chevyresto/5038.htm The 12-6 volt reducer mentioned earlyer in this thread wont work . The original horn spesifications shows higher Amps in usage . Martinius.
Looks like this thread has morphed from basic correct horn hook up to a discussion on voltage reducers You can use the old fashioned ceramic "Volt A Drop"... they have a double coil in them {one hook up for low amp draw accessories & one for heavy amp draw accessories} but they are rather large & hard to hide....they get hot....& the internal coil wire is prone to failure after only a few years of use. I prefer the solid state constant duty reducers.... never had one go bad no mater what I hooked one up to & they are small & easy to hide....
Reducer question Does the last model shown by Joe have an output of 10 amps ? Are there any reducers you`d can buy with a higher value like 20 amps ? The 6 v horn have an spesific of value 17- 21 amps. Martinius.
Impedance is measured in ohms, not amps. Technically, it is measured at a specified frequency, zero (DC) in this case. For our purposes impedance = resistance in a DC circuit. The 17 to 21 amps is a current measurement, not an impedance measurement. IF that is the correct amount of current draw for the horn (and using 20 amps) plug these numbers into Ohm's Law ( I = E/R where I = current in amps, E = voltage and R = resistance [ impedance ] ) you get 20 = 6/R or solving for R, R = 6/20 for a resistance of 0.3 ohms. In order to use a simple resistor ( like the gold color device that DZT pictures above ) to limit the current to the horn to 20 amps when supplied by 12 volts the resistor needs to be rated at 0.3 ohms and at least 120 watts. I'm pretty sure that the resistor in DZT's picture is rated at 100 watts, which is a little low, but as long as you aren't Italian (uses horn instead of brakes ) it'll probably work OK. Just disconnect one wire from your horn, connect the wire to one end of the resistor and then connect the other end of the resistor to the horn terminal the removed wire was previously connected.
Horn Foolishness Or ; Just do like most have been doing for well over 50 years : toot the damn thing on 12 volts and never have any problems . Sheesh .
Thanks for the explination Bill This is a thourough explination on a field i dont know to much about. Trying to understand how it works though ? Thanks Martinius.
I don't know if I overlooked something, but According to Ohm's law, without using a voltage reducer you will be pulling half the amps at 12v that you would at 6v since you have doubled the voltage.
Not true. Using the same load (let's say the horn in question) you'll pull twice the amps at 12 volts as you will at six volts. The resistance of the horn stays the same no matter if you are applying 6 volts or 12. Using Martinus' horn with a resistance of 0.3 ohms ... I = current in Amps E = volts R = Resistance in Ohms I = E/R (Ohms Law) I = 6/Resistance of the horn I = 20 amps (at 6 volts) I = 12/Resistance of the horn I = 40 amps (at 12 volts). If you REPLACE the 6 volt horn with a 12 volt horn the current would go down considerably, maybe even the half that sidewinder states.
