I am confused with the wiring diagram for the horn switch on my 1927 Chevy National. I have power coming in and out of the horn. The wire coming out of the horn is "grounded" to the steering column. I tested it with a with a simple light to ground tester and I have power coming out of the wire that is "grounded" to the steering column. So how does the horn button operate? What is the purpose of grounding the wire? Help!!
If you have positive power on both horn terminals then something is wrong inside your horn and I wouldn't push the horn button or it could arc. There should be a hot lead that comes from your lighting switch (after the fuse I believe) to one terminal on the horn. There is then a wire that comes from the horn button to the other terminal of the horn. When the horn button is pushed it completes a ground connection to the horn thus turning the motor inside the horn. You should have nothing at one of the terminals + or - but hot on one with switch on and negative on the other only with horn button depressed. The horn button pulls ground from the steering column being grounded to the chassis good.
I have taken the time to find another good motor that does not have an internal power leakage between the horn terminals. I cleaned up the brushes, armature, and made sure there were no loose connections. Tested the motor again and no leakage. I installed the motor and now I have power on both terminals!!! I took the wire from the ground wire and that is hot as the horn blasted away. I an not a good electrician and do not understand that the terminals were working correctly before I installed the horn on the truck? What is going on here? I need help to understand the problem!!!!
There are two wires to the horn. One wire is the "hot lead" from your lighting switch. If you disconnect this wire from the horn you should measure 6V from this wire to ground with your meter. The other wire to the horn goes up the steering column to the horn button. Pressing the horn button will connect this wire to ground. Therefore with the wires connected to their respective terminals on the horn, you have an electrical path from the lighting switch, through the horn, and to ground when the button is pressed, completing the circuit.
With everything connected and working properly, and the horn not on, it is normal to measure voltage from both of the horn terminals to ground. The electricity is flowing from the lighting switch, into the horn, through the windings in the horn, and out the other horn wire and up the steering column. The electricity is looking for a path to ground. When you press the horn button, you are giving it a path to ground and making the horn blast.
pgbare sel I owe you an apology and am sorry I added confusion to your problem. I had it in my head that the fields of motor were separate (ground and hot) but coachman is correct. I checked mine tonight and it functions the same as he describes. David
Thank you for clarifying the flow of electricity for me. Grounding to a steering column is a new concept to me. I checked over the connections and power flow and got my horn to work!! I really appreciate your help Paul
