Siren not sounding

I have a S14 240sx and with a Viper 791 installed and the siren output doesnt work. I only get a .05 reading when i tested the output at the brain. Is there any way to make the siren sound. I already tried to get a signal from the parking lights but it sounds when i'm in remote start. I also have air horns set-up and it sounds those too. I was thinking about using another alarm i had laying around and use it's siren output but I dont know if that's possible. The other alarm is an Avital 2300 but i dont have the remotes to it. Any help much appreciated. Thanks.

i dont know much about alarms but if your only getting a small reading, then try and use a relay