While looking through my collection of parts tonight I noticed that about half of the steering columns have a larger horn wire "trough" and the others have a smaller horn wire tube.
Can I assume the difference is due to the year of manufacturing? If so, what years were the different styles used?
Thanks in advance, Mark.
Top one is a 15 looks pretty nice.
When electric horns were introduced on 1915 cars they had only one wire that grounded at the switch, and therefore a small tube. If you turn that 1915 column over and look at the other side, you'll see two little screw holes where the switch was mounted on top.
In a previous thread, I learned there were two sizes of the open U shaped tube, a smaller one for one wire which followed the tube on the top photo. Then it was made larger to accommodate two wires for the battery horn.
Allan from down under.
You also needed the larger tube to run the head light switch wires in along with the horn wires after the switch was moved from the firewall to the steering column up to when the head light switch was moved to the instrument panel around 1919/20.
Being an electrical dummy, I have a couple of questions:
1. All of the wiring diagrams I've seen show a hot wire to the horn button and then a lead to the horn. The horn is grounded by virtue of the fact that it's bolted to the engine block. Why have I never seen a diagram with just the one lead you describe to the horn switch which would ground it to the steering column?
2. If the first electric horn cars had only one wire that the switch grounded to the column, wouldn't there need to be another wire somewhere from the steering column to ground since they had a wood firewall? Otherwise you'd be relying on ground through greased fittings, which doesn't seem very reliable to me.
My '18 TT has the '15/'16 style steering column with the button on top held in place by the 2 screws. Inside the switch are 2 electrical terminal screws. By the time I got the truck the horn wire(s) was long gone (the horn too for that matter). Also missing is the horn button, just the metal parts remain. The tube is the smaller one and is fastened with tabs line those on the upper column in Mark's photos.
I've always been curious about this and this thread seemed a perfect opportunity to ask.
2 The steering shaft, throttle rod, and spark rod all pass through the steering bracket, which is bolted to the frame. Even with some grease, there's plenty of ground.
All the various horn buttons are available new from the parts dealers.
The magneto horns generally have two terminals, one is the hot wire from the power source, magneto, the other to the grounding wire to complete the circuit when the button is pressed down. The steering column acts as the ground path. So the horn can be mounted to the wood dash. As it is there is one bolt that mounts the horn to the base of the steering column through the wood dash and would make a grounding path.
Thanks Steve and Mark. I get it now.