Getting a wire through the steering column
 

I wish I could get a better look in there to see if this is straightforward, impossible, or somewhere in between. I want to put a switch on my steering wheel, which will run to ground (like the horn). I'm willing to lose my horn functionality if I need to, but I do not want to use the sliding plunger contact and ring that the horn uses, since it doesn't give me reliable enough contact when the wheel is turning/flexing/shaking.

Has anyone done this? The goal is to have a wire provide ground to a relay (in this case, it's for my active rear wing). It's for a 1972 911 steering column.

Rig up a "Clock" spring inside/behind the steering wheel?

1:22 - 1:26 in this vid
https://www.youtube.com/watch?v=hux78ZoPcAI

Seems to me a difficult problem without the ring as the steering wheel turns so far, it would stress the wire/connections. If it were me, I would probably try a remote switch. I would probably try to find an aftermarket remote start kit that had a small pkg (uses lithium watch battery) or similar and attach that to the wheel. The relay for the remote start should be plenty big for the wing. Probably need to wire in a circuit to make the relay latch until you push it again.

Well, I found a way to do it that didn't involve a hard line connection to my steering wheel.

Of the two junction points in the horn's electrical path, the one for the horn that is a part of the quick-release could not be made to fail. I have conductive grease on the contact point(s) as insurance.

That conductive grease is messy.

http://imageshack.com/a/img661/6204/QNyfnp.jpg

The horn contact in the column that rotates a sprung piston around a little copper track was the one that could be made to fail intermittently, so I'm not using it. Instead, I have a length of coiled wire (a guitar plug-in line) so that there's enough slack to wrap when the wheel is turned. The switch is a push-button type that I mounted in one of the steering wheel holes. It has to be held down, which gives me a form of 'dead man' protection. As soon as I let go, the wing goes back to the high-downforce position.

http://imageshack.com/a/img538/6067/eGkmUV.jpg

I'll test it later this month.

Have you been reading Patrice's thread? His active wing is pretty cool. I can't wait to see what you come up with.

Where did you source the cord and button?

The guitar plug-in came from Amazon. My thinking was that out-of-control guitarists would test the durability of the thing pretty well. The button was something I had on hand. It's a plunger-type switch. I'd previously tried a rocker-type, which I worried was less safe.

I'm looking for a PTT that fits in the Momo holes, yours appears to do that.

The wheel is a Mod07. If I remember right, the switch is made for a 16mm (5/8") cut-out. I think my wheel had slightly more space than that. I used a thin washer in back to snug up the fit.

I've got a bunch of the switches. PM and I'll send you one.