This may sound stupid but I have a quick question. On the eclipse I bought it already has a viper alarm installed my question is why is it when i lock it sometimes and unlock it will churp and let me know and sometimes it wont make any noise at all. What is causing this?

you might be hitting the "aux" button before you hit arm or disarm on accident. Usually with DEI alarms if you hit "aux" then the arm/disarm button it will arm/unarm silently.

Yep, that or you have a bad wiring conection to the siren. Possibly even a siren thats going bad. Look at your siren and how its mounted. If the cone of the siren is pointed up, then water and moisture can build up in there and make them go bad...

On some alarms even when set to "silent set" they chirp when you come back to unlock them because they were set off while you were away.........maybe this helps maybe not but hey :+