Kimchi Un

I've seen First30Minutes change his Ambulance siren etc in his gta 5 but I don't know how I am supposed to change the siren for the els ambulance/firetruck/sheriff suv/fbi cars. Can someone help me and not leave this topic left alone?

I haven't edited my els xml files for the vehicles and the siren pack I used was the American Sirens Pack located here: https://www.lcpdfr.com/files/file/11738-american-sirens-pack/

So I have all els vehicles in my gta 5 and I have installed a custom siren pack. But this custom siren pack is supposed to have unique sirens for ambulance, firetruck, sheriff suv and fbi cars. If anyone can tell me how to directly change the siren for those vehicles, I would be very appreciative.

Yes

What I mean is that the standard police siren is locked to every emergency vehicle and the other sirens for ambulance, firetrucks, fbi vehicles etc. are cancelled out and replaced with the standard police siren of the siren pack. Edit: it only happens when I have replaced default models of the vehicles

So I installed a siren pack which changes sirens for all vehicles in my game. I have different replacement vehicles as well installed but they are all locked to the one siren. Same goes for ambulance and firetrucks. There is different sirens for fib cars, sheriff suv, police bike and the ambulance and firetrucks. How can I change the siren on these?