Some interesting adventures with the Grant steering wheel. Like I mentioned above, the horn would blow when the turn signal stalk was moved. After some dicking around, it would also blow when turning the wheel more than 45* or so.
Lots of investigation led me to multiple issues.
I blew the horn about 15 million times trying to figure out where the short was coming from. The wife was pretty annoyed. I finally disconnected the horn wire under the dash, and setup my multimeter showing continuity to ground on that wire, so it would beep at me when the horn circuit was being triggered. On the 61 falcon, the horn button on the wheel grounds a wire, which triggers the horn relay. Luckily there is no hot side to short to ground in the horn assembly in the wheel.
First, the turn signal issue. It turned out the turn signals were causing the horn to blow because I needed to readjust the steering column to wheel hub gap. Grant of course mentions this nowhere in their instructions.
This was causing the hub (and therefore the grounding slip ring on the bottom of the hub for the horn contact) to rub on the turn signal canceling cams when they were activated (which pushes them inwards). These are the springs top and bottom in the next picture. The horn contact is on the left.
Once I set the gap better, they couldn't touch no matter which way the turn signal was engaged, yet the spring loaded horn contact could rest on the grounding slip ring. Which leads to the next problem.
The horn would blow when turning the wheel off center. At first I blamed Grants crappy hub design. I still don't like it, but I don't think that was the problem. I drank a couple beers to charge up the head computer, and realized I should check out the horn contact after looking at the hub when I removed the wheel for the 10 millionth time. I noticed I had wrecked the horn grounding ring from turning the wheel trying to figure out what was going on. (Calling Grant tomorrow, hope I can get a replacement hub)
Turned out the spring loaded horn contact sits in a plastic base, and that base was cracked. It looked OK with the wheel off, but when the hub was in place and pressing against the contact, the cracked base let it slip sideways. This gouged up the grounding ring, but caused the horn to blow when turning because it would rub on the self canceling trigger (black thing in the center) that I had swapped over from my stock wheel.
I removed it and it became clear just how bad of shape it was in. I guess it held up OK with the old wheel in place, but after being relieved of pressure after 60 years, the plastic base was toast.
So, I got the wheel back on, insulated the horn wire in the column, and the car is good to drive. I ordered a NOS horn contact/base that should fix the problem. I'll call Grant tomorrow and try to get them to send me a replacement hub, if not guess I'm buying another mounting kit ($30 more down the drain). We'll see.
And sorry for this crap picture with no light, but I got my console put in. I love these things, had one in my Mustang forever. Unfortunately it's made to be pressed in between the stock bucket seats, which hold it steady (also velcroes to the carpet). These Procars must be narrower bc there was a large gap and it was much too loose. I'm going to mount it to the floor with a bracket or something, but for now I took some wood scraps I had laying around, covered them in leftover headliner material, and used them to shim the console between the seats. Not ideal, but will work for now.
Til next time! I looked through the build book and have a pretty cool parts list for the engine in the car. Will post that up soon.
That could go down hill quickly! But that's the beauty of this place, its all in fun. 
