Pain generators and extra siren

Have done a search and have found basically that i need a relay i got that. I also found that with the relay they will be alittle off sinc. I want to add an additional soft cherp and two pain generators. Couldnt i just disconnect the red wire to my existing siren, use that on the relay and then connect all four siren outputs to the relay to keep them in sinc? Thanks for the help in advance.

Yes, use the (+) siren output wire from the brain to trigger pin85 of the relay. Of course, connect all 4 siren to pin30. But keep in mind, if you also have 520T (backup battery), wiring this way will make all 4 sirens silent when the thief disconnects your battery cable. Yes, the siren output from the brain will energize the relay, but then your relay itself loses 12V from pin87, thus pin30 gets no 12V(+) output to the sirens.

Yes, but even better, swap your 85 and 86. If you don't use 520T, you should have at least one siren with built-in battery backup. Or else all 4 sirens will stay silent when your battery cable gets cut off. Usually people installing more than one siren always have some sort of 520T. Otherwise what's the point. You even can get a 520T to push the alarm brain and another 520T (with at least 7Ah BUB replaced) to drive just your lights/horns/sirens. Another even better approach is to get an electronic hood lock. BTW, my plan for my own car is to hook up a train horn and activate it with 528T with a delay. You want 4 sirens to get people attention, train horn could wake up everybody.