98 civic coupe alarm issues/viper

just bought this car couple weeks ago for my sister. I believe the alarm is a Viper350HV....its the basic one they sell at best buy. IT does have relays for the door locks and stuff. Everything on the alarm works fine EXCEPT the siren. Orginally when I got the car, the siren didn't work at all. There was no ground So I grounded the siren and it works but it was very soft...So i thought it was a bad siren. I changed it out to a DEI 514 soft chirp one but still the same thing. I check to see how much power is at the power wire to the siren from the brain and its at 1v...pretty sure its suppose to be more. My guess is something wired wrong? or power to the brain? I have to drop the lower console and take a look at the wiring under there. Last time I checked the wiring was a mess for the alarm so I guess i'm going to rewire it while I try to fix the siren. anybody have suggestions?

Does the alarm feed a brown wire to the Siren's red and the siren grounded through it's black. If so voltage should be 12v+ on the brown when siren is triggered.

Good point t&t  are we talking soft chirps here, is the black lead cut at the siren?  But we should still get 12v+ fom the alarm's brown on siren trigger. That's the second thing I would test, after extending the siren leads to the battery, red to pos and flash across the battery just to make sure Siren is OK.