What years used this switch and how was it wired to the lights? Was there no light switch on the dash panel, or was this before there was a dash panel? Thank you.
I would presume you are talking about the steering column mounted so-called "Combo" lite switch/horn button thing. The button/knob turned and had 3 positions "off/dim/brite" and you pressed it to honk the horn. It was powered by magneto since the car that used this switch had magneto horn and magneto lites. There were 4 wires that went from the base of the steering column up to the "combo" and they were wired as follows:
wire #1 was wired to the magneto and I am pretty sure it picked up that connection at the magneto connection of the coil box. This wire was the source power for both the horn and the lights. When the horn button was depressed this wire made connection to the horn wire which then supplied magneto power to the magneto horn mounted at the base of the steering column. The other terminal of the magneto horn was then wired to ground until later version had only one connection with an internal ground of the horn via its mounting bracket.
wire #2 was the horn wire which was wired from the magneto horn to the pushbutton connection for the horn button mechanism. Unlike 15/16 horn this wire did NOT ground to the steering column and in fact none of the 4 wires went to ground.
Wire #3 was the lights BRITE connection which went to one of the 3 wires of the dimmer coil mounted on the engine side of the firewall near the steering column point where it passed through the dash.
Wire #4 was the lights DIM connection which went to another of the wires of the dimmer coil winding.
The dimmer coil has 3 wires on it. ALL DIMMER COILS were electrically the same but the ones used with this combo switch had long wires on them while later versions were mounted behind a dummy panel that covered the ammeter hole in the metal dash trim plate.
The dimmer coil is a tapped inductor with one winding thus it has 2 ends and a tapped point in between and at least part of the coil was in series with the headlights for the brite connection wire while the entire coil was in series with the headlight for the dim connection wire. The 3rd single wire from the dimmer coil was the one that ran to the lights and the dimmer coil reduced the AC current through the bulbs to a safe level to keep them from burning out and the combo switch connected the magneto power to the entire coil for dim and for part of the coil for brite. Now the dimmer coil moved around a bit during the years that it was mounted on the engine side of the dash but it was mounted there early on via wood screws and spacers. The spacers were in fact the same ones used to mount the points on a coil. Still later they made a bracket out of sheet metal.
The combo switch and dimmer coil thing started in 1917 or late 1916 - I honestly don't have the info at the ready as I write this but I don't know for sure when the combo switch went away but the dash mounted push pull switch next to the coil box was the earlier 15/16 light switch and the combo switch replaced that. The 15/16 cars used raw magneto to power the headlights and those were 9V bulbs wired in series so if you gunned the motor your magneto could easily go over 20 volts and the lights would have very short life. The dimmer coil prevented that by putting a simple inductance in series so that as the AC frequency of the magneto increased with speed and the voltage went up, the AC resistance (called reactance) would also increase so the bulbs had a somewhat crudely regulated source of AC current for the "cheap car" which had no battery.
Hope this helps.
Hi I have this hope that will help
A dimmer for magneto lights? Now, that's funny!