I have similar issue few months ago. My car's alarm sometimes activated in different places without any reasons. I cannot switch off the alarm using the remote key. I opened and closed my car may times but siren still howling. Sometimes silenced after few open/close procedure and sometimes after short ride. I cannot find any regularity of the issue. So finally I did not locked my car on streets. Few weeks ago I red this post and find the schematic here. And Eureka. I remember like few months ago I found that the hook of lock's glove box was loosened. I screwed it immediately but in wrong position (too shallow so the cover of glove box protruded a bit over the surface of dashboard). According to the schematic I found that if you push down the switch of glove box you hear two clicks: first click is switching the lamp and the second click is switching the sensor. So I screwed the hook in right position (deeper inside to the glove box). After that I have hot any issue with the alarm. Probably the loosed hook was directly cause of my problem.