Honda Odessey Alarm does not sound

I just got a 97 Honda Odessey, the alarm (08E51-SV4-1M0F2) does not sound, but otherwise is fine. The light flashes and the keyless entry works when I use the remote to lock/unlock the doors and arm/disam the vehicle, except that there is no beep. When press the panick button the light flashes and the ignition is disabled, except that the siren does not go off. The alarm system does not have siren and was set to horn. The horn is working fine. I do not have the owner's manual of the alarm, so I do not know if the alarm module is bad or if is was set to silent the alarm. Anyone can help?

Really appreciated.

Thanks for your reply.

The alarm is the factory OEM alarm made by Honda. 08E51-SV4-1M0F2 is the catalog number. I bought the car a few weeks ago. The seller said it was working. But the manual of the alarm was lost and he did not even know it stopped working. I noticed the problem a few days after purchase.

I tested the alarm according to your advice. When I pressed the panick button, the horn wire (color: light GREEN/ blue) has 12 volts of voltage (on and off), no alarm sound, a 4-pin relay under the driver's dashboard clicks. The voltage was on and off along with the flashing light. When I shortcut the 4-pin relay, nothing happened. It seems that the horn output is working but the voltage does not affect  horn circuits of the vehicle. The horn of the vehicle works fine.

I am still looking for the location of the horn relay and the horn fuse. Any idea where it is? What could be the real problem?

Thanks again.

I finally found the problem. It turns out that both 2-pin connectors of horn harness of the alarm was notconntected to the left horn. Instead, they were connected to each other. Obviously someone must have disconnected it. After I break away the vehicle horn connectors and connected them to the 2 pin connectors of the alarm horn harness, the alarm begin to sound.

Thanks for your help.