Horn button wiring

[Jameel]

I understand how the horn buttons work in early 911's and 914's through the spring-loaded plunger installed in the steering wheel itself. But one detail on some cars has me scratching my head. On a couple horn buttons I have here, under one of the screws that holds the spring-loaded clip to the underside of the button there's a single spade terminal. On both my examples the spade is oriented so the tip of the spade makes contact with the clip. Since it also makes contact with the screw, there is continuity between the spade terminal and the main body of the horn button.The spring-loaded clip, since its always in contact with the steering wheel hub (and thus chassis ground) is grounded, which means the spade terminal is grounded. On my '71 914 the horn button wires up just like on an early 911, with the spring plunger, but it's button also has this spade terminal. So I'm not sure what purpose this spade terminal serves. I've also seen this same terminal on early batwing buttons, which also show evidence of the use of the spring plunger. If one attached a theoretical horn ground wire to this terminal, then twisted the button into position, the horn would sound continuously--there would be no break in the ground as normally provided by the "ground ring". I'm attaching some edited pics I borrowed from other posts to illustrate.

[Jameel]

Friendly bump. Any ideas?

[edmayo]

Leave the spade off, not used on 911 application.

[Jameel]

Thanks Ed. But why is it on a 911-only horn button? At least I'm fairly certain the batwing was 911/912 only.

Can you also explain in what situation it *was* used in?

[edmayo]

Someone put it there. 914's used a wire to a spade instead of the button contact used by Porsche

[Jameel]

Thanks again Ed. I'd still be interested in knowing the ground path that's used in that context, if you or anyone happens to know. Connecting a ground wire to that terminal would mean the horn sounds continuously since the screw the terminal is on chassis ground. I've seen 914's with that terminal riveted or soldered onto the ground ring (the part the spring loaded plunger contacts on a 911) which makes sense since it's disconnected from the ground path until pressed down onto the steering wheel hub. I don't think its just chance that this terminal is here. I've seen it on many steering wheels.