My new toyota yaris dashboard is rattling. help!!!!

I have a 2003 Toyota Vitz (in Japan) which is a Toyota Yaris in the states. There is an electronic rat rat rat rat but extremely fast sound..... this noise sounds like a regulator or some electronic component going out on the passenger side dash board. The noise is random and does not link w/ AC b/c I've turned off the AC and it cont. and will start up again despite AC being on for a while, more during morning times but sometimes during a drive along the way. It is a very annoying sound and will act up for a few days and will disappear for months before returning. Does anyone know anything about this?

This is some work that needs your first hand observations.
You must take the car to a difficult rrough road to simulate the noise/rattle , identily if within the dash or if the vibration is a transfer from the steering section or the suspension.
Make someone drive while you observe, identily and find the rattle point to tighten or replace the part.