I posted this problem 2 weeks ago, and out of all the questions that were submitted during those 2 weeks, mine was the only one that didn’t receive an answer! Surely someone can help, so here I go again.
My 2001 prius has an alarm system that goes off without prompting, anytime, anywhere. It happens about 2 or 3 times a month, and it’s especially annoying in the middle of the night, not only to me, but to my poor neighbors. The toyota dealer has no answer, the toyota website is clueless, and we are desperate. The system is one which cannot be dismantled. A toyota mechanic replaced a relay, but that didn’t help. Can anyone out there??
Is this an aftermarket or factory unit? Who told you that it could not be disconnected or removed? Any alarm can be disabled or silenced. It just takes a little study of the system to do it. I suggest taking the vehicle to a good independent mechanic and tell them you want the alarm disabled. I, for one, see no reason for car alarms anyway. Mainly for the problems you are having here. I used to work near a large parking lot in a mall. Cars and trucks would sound the alarm all day and all night and no one would go near them including the mall security patrol.
I had this problem, not with my Prius, but on a 99 Ford Escort. Before figuring out the cause, my first solution was to stop using the automatic door locks, which also engaged the factory alarm, and to lock the doors manually. Later I found the problem was that the latch under the hood had rusted to a point where it was very difficult to keep this hood completely shut. Not so much that it would fly open, but so there was no need to release the hood before going to the front to unlatch it. So there were times, random middle of the night times, when the alarm sensor under the hood would not keep contact and just go off. Once I was made sure everything was fully latched, I went back to using the automatic door locks and never had the problem again.