Purney,
I hope I'm not dominating this thread! You are backtracking, trying to find where you have power and where and why it stops. The key switch gets power from the ammeter and switches it to the coil and (I think) the fuel gauge. The horn and lights are not switched so they won't be a good indicator of a defective switch.
If you turn the key on and off, do you see the fuel gauge move? If you do, it means the key is getting power..it also means the set of contacts is getting power. If I'm correct, the coil is on that same set of contacts and this would mean there is a wire problem from switch to coil.
The 'moving fuel gauge' test isn't 100% reliable. Sometimes the fuel gauge is defunct. If you are agile and flexible, crawling under the dash with a good trouble light and actually testing each key switch contact is the next step.
There will be a terminal that has power all the time, and at least one more that have power when the key is turned on. Enough for now!
Stuart
