Early T Horn Button

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Model T Ford Forum: Forum 2009: Early T Horn Button
Top of pagePrevious messageNext messageBottom of page Link to this message  By William C Severn on Thursday, May 28, 2009 - 06:32 pm:

About a year ago I bought a horn button for my 1916 Touring car. It is the early style horn button that mounts on top of the steering column. It was in very good shape but I still took it apart to clean the inside contacts, re-wire it and paint the outer case.

My call for help from the forum is this; the horn button that I have has one contact that grounds to the steering column. How does this work with the horn wiring diagrams I have seen on the forum? All those diagrams show power coming from the magneto then passing through the horn button and reaching ground through the horn. This horn button would indicate that the wiring went from the magneto, through the horn and was grounded when the horn button was pressed. On the other hand, the magneto horn that I have shows that the terminal grounds through the horn itself.


Is the horn button wrong or do I have the wrong horn? Can I hear from owners of 15, 16 and 17 T's?

Thanks,

Bill


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Sims on Thursday, May 28, 2009 - 07:56 pm:

My early 17 goes from the mag to the horn and then is grounded thru the horn button.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David_Cockey on Thursday, May 28, 2009 - 07:58 pm:

The magneto horn on our 1916 T has both terminals isolated from ground. It's wired as you described, through the horn then to the button which grounds when pushed. The wiring diagram in the 1915-1916 owner's manual shows the horn wired in this manner. The same wiring diagram appears through 1920.

The 1921 owner's manual has a wiring diagram for cars which starter which used a battery powered horn. It shows two wires to the switch, one from the terminal block, the other to the horn.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Thursday, May 28, 2009 - 11:46 pm:

Guys - let me shine some light here if I can. Starting in 1915 with that version of the mag horn and continuing up until but not including the "combo" light/horn button, the wiring was as mentioned namely that the wiring was from magneto to one horn connection and then from other horn connection to the button and there grounded at the column. Either horn connection could be used for either wire since the source is AC but both of the horn connections must be isolated from ground. Only 1 wire comes to the horn button up the wiring tube. The earliest 1915 cars had a loop of wire and the button was in fact clamped to one of the steering wheel spokes. Bet that made things interesting on sharp turns and horn honking. Starting with the "combo" light switch, the magneto wire was brought all the way up to the switch where it was connected via horn button to the horn wire which then ran back down to one horn connection. The other horn connection went to ground simply by having the fiber washer removed at that remaining mag horn connection which then grounded it since the horn frame was connected by one bolt to the steering column base. The reason why the mag wire was taken up the column was that the combo switch could at that point connect that same magneto wire to either of 2 connections (brite or dim) which came back down the column to be connected to the dimmer coil which on these first 1917 cars was mounted to the engine side of the dash. The dimmer coil was used with the "combo" switch to start and then later moved to a spot behind the ammeter block off panel on the later T's.

To sum it up - cars with simple button on column (typically 15/16/early 17?) use fully isolated connections on both mag horn terminals while cars with combo button/switch and later cars use the mag horn with one connection going to ground and the mag wire being supplied to the horn button with the horn hot wire coming from the other side of the horn button such that neither side of the horn button is grounded in these later cars.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim on Friday, May 29, 2009 - 12:38 am:

John Regan--- I notice some magneto horns only have one terminal. When were they used?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Warren Mortensen on Friday, May 29, 2009 - 08:01 am:

Those were used on later non-electric (no generator furnished) cars. The horn button had two wires (one going up and the other going down to the horn). One wire of the horn armature was connected to the horn case internally. Since the horn was bolted to ground (engine block or steel firewall?) it needed only the hot terminal.

Regarding the later electric horns that operated on the DC circuit rather than magneto: I believe Ford didn't start furnishing cars with this horn until well after the gen/battery option was offered. Early cars with generator option still utilized a mag horn until sometime in 1922 if I recall correctly. Regan may be able to give better details.


Top of pagePrevious messageNext messageBottom of page Link to this message  By William C Severn on Friday, May 29, 2009 - 11:16 pm:

Thanks for the great input from everyone. I should be able to get the horn working in short order.

Bill


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Saturday, May 30, 2009 - 08:59 am:

Warren is correct. Battery horn was supplied first in early 1922 and believe it or not that first battery horn was mounted to the firewall with a rare bracket known as 6237B which was similar to the pre 1922 mag horn bracket (6437A) in that it was "butterfly" shaped but it had a "z" shaped bend in the middle of it to mount it forward of the firewall since it had a large and deeper motor cover than the mag horn. This bracket was only used a matter of a few weeks before the horn was fitted with a new bracket (6437C) and mounted to the motor via one head bolt and one water inlet bolt. The final bracket was 6437D and was the typical 26-27 bracket which mounted the horn via the water inlet bolts only.

What may not be obvious is that the magneto horn casing was always grounded even on the early cars wthh wood firewall because one bolt of the mag horn mounting was one of the steering column mounting bolts at the steering column firewall flange. Thus when the mag horn began to be powered by a single wire mag lead coming from a pushbutton, the horn was grounded either by that steering column bolt on the early cars or by an engine bolt on later ones. Warren nailed it on the single connection mag horns. Those were later. Earliest mag horns came in all sorts of varieties and shapes but generally were characterized by having rather short snouts (called the horn bel) and some of those were painted brass. Later mag horns had the longer snout like the battery horns and were steel.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Sunday, May 31, 2009 - 06:25 pm:

OOPs! The early battery horn bracket with the offset Z bend in it is 6437B. I incorrectly called it 6237B.


Top of pagePrevious messageNext messageBottom of page Link to this message  By William C Severn on Tuesday, June 02, 2009 - 04:28 pm:

Another question about the early horn button. What kind of a screw attaches the button to the steering column? If it is a machine screw, what size and what threads?

Thanks,

Bill


Top of pagePrevious messageNext messageBottom of page Link to this message  By William C Severn on Wednesday, June 03, 2009 - 03:48 pm:

I think I answered this one myself. My horn button took two machine screws that were 8-32. The length should be about one quarter of an inch.

Best to all,

Bill


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Wednesday, June 03, 2009 - 06:05 pm:

Well that settles that. I was going to check on my son Johnny's '16 roadster one evening for you but that would have been my guess. I remember they were round head slotted and yes about 1/4" long but I couldn't remember if they were 8-32 or 10-32 but I know they were fine thread. His car has a most interesting short snout mag horn on it. John Mansville brand as I recall. Really was shocked at the name plate on it. I expected something else but don't know what.


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