We have a 2004 Toyota with a factory installed car alarm. The alarm goes off randomly. Sometimes a few times a day, some days not at all. No physical disturbance is setting it off (it does it even sitting in our closed garage). However, we noticed that it seems to happen when my daughter's cell phone is in the car. I am still trying to confirm this relationship (by having the phone in there, or not having it in there, and seeing when the alarm goes off).
Could the cell phone be setting off the alarm? It's nothing obvious, like the phone being on "vibrate" mode, and receiving a call. Could the phone be sending a radio signal that is at a frequency that sets off the alarm (like the frequency of the emergency button on the key pad)?
We had it at the Toyota dealer, but they didn't find anything (this was before I made the cellphone connection).
Thanks for any help!