Ive searched all over and couldnt find it.
Can someone please explain how to hook up a relay and a switch to kill the ignition and when power is supplied blow the horn? Like mentioned on the site before.
I under stand ill need a 3 pin toggle switch 1 Input and 2 outputs
Then Ill need a relay
but how do it hook it all up and what kind of relay will I need?
What input to the switch and what input to the relay?
I thought I saw a diagram but cant find it either.

try some corvette sites if no one here has a diagram for you, I don't have a scanner sorry, but corvettes had a real simple alarm standard from 1972 just like you described, very basic, using a key switch, (on off) and a flasher can to honk the horn, would be easy to also incorperate an ignition kill as well.
Dave

This is a crude representation of what you would need to accomplish and would only help if they busted the ignition switch and tried to start it that way.

This is going to sound bad…. Any knowledgeable theft is going to for the wires under the column but because speed is always a factor a slide hammer is often used and this would be an effective deterrent in that case.

On most GM cars the crank wire is purple you would need to cut that and wire your toggle so that when the switch is in one position the circuit would be closed and you could start the car. In the other position the switch would be open BUT contact form the ignition would send power to the horn not the starter.

This is a diagram (http://www.midwestlinings.com/images/alter%20lights.JPG)I made up for alternating lights like the cops have with a 5 pin relay and a flasher you can do a lot of cool things.

http://www.midwestlinings.com/images/cheap%20alarm.JPG

How big of a toggle switch is needed for this setup? Would a 15 amp switch do all right?

Kind of depends on the condition of your starter and your engine. There is a constant 12 volts to your starter at all times and this is the power the starts the car. The 12 volts from the purple wire just engages the larger battery cable. (Theres more to it than that but this is not a starter lesson) Also run a 30 amp fuse if this is something you’re considering.

Disclaimer: Please be careful, I will not be held reasonable for someone burning down their dream.

Sorry,
But doesn't the wire from the neutral safety switch go to the middle terminal? When the switch is in the up position current will go flow from middle terminal to top terminal, when in down position current will flow from middle terminal to bottom terminal.;)

Yea it does, I got it put together today and it works I just need to find a clever spot for my switch now. Ive got and Idea that Im gonna try and do but I havent figured out how Im gonna do it yet.

Why not in the center console, if you have one?

This is a crude representation of what you would need to accomplishSorry it was 4 degrees outside, I didn't want to experiment, but I knew that would get him close.

EDIT – The correction has been made to the diagram above. Glad you got it figured out.
If I can add one more thing, (Although it would be the easiest) under the dash is not a good location for the switch.

Why not in the center console, if you have one?

Cause I aint got one. Bench seat here....

Danny,
This would require removing the 4 screws form the door seal plate but if your wires are long enough…. run them along the edge there and under the carpet to the bottom of the seat. You will have to get crafty and make a bracket or zip tie the switch BUT I wouldn't look under there…….

The harder you make the install, the harder you are going to make it for the bad guys

Several different ways to do it but you could get a little more sophisticated and use a DPDT switch and a latching relay so once it's energized by a thief he can't just turn it back off.

Another thought is operating the horn relay (ground wire) rather than the horns directly (hot wire) with a DPDT relay would be much less amp load.