Vehicle: 1999 Corvette C5 Convertible
Question: I have added a motion sensor to the hood pin sensor wire. Easy.. What I want to do next is to add a siren, as the horn isn't enough. I could add a Siren tied diretly to the horn, but this means that when I honkt he horn the siren also blasts.. It also means that the siren pulses on and off with the factory horn instead of staying on.
How do I make it so that the siren trips only when the factory alarm trips.. Does anyone know of a armed wire or something similar? And how to keep it on until the car resets of is disarmed?
-Brian
Well, as far as being able to honk the horn normally while driving, you could do it this way.
Attach the siren's positive wire to the horn's positive wire.
Attach the siren's ground wire not to a ground...but to the car's main ignition wire. When the car is on, the siren will not work. When the car is off, the ignition wire will give the siren a ground, allowing it to work.
Even though we don't typically fuse a ground wire, you should in your case. Attach an inline fuse close to where you pick up ignition power; this way, if your wiring shorts out to ground, the fuse will just blow---your car will still be driveable until you can fix the trouble.
Also, you don't necessarily have to go to the steering column for the ignition wire---you might find a wire underhood that will test the same way. If there's an underhood fuse box, I'd start there.
I still haven't thought of a way to keep the siren on steady while the horn is honking on and off, but at least you have a solution to the siren-while-driving issue.