I’ve got a random noise under my dashboard in my 2001 Toyota Avalon. It lasts for about 15-20 seconds. Sometimes weeks go by and it doesn’t happen then a number of times a day. Sometimes when I start it up, other times randomly through the day while driving.
I was very lucky and was able to capture it and post to YouTube. Anyone have an idea what it is?
More than likely, this is a case of a blend door in the HVAC system that is malfunctioning.
Is your HVAC system operating normally in all of its modes?
I would guess that at least one of the modes is not operating properly as a result of this problem.
The rachet like sound?
My guess (and the experts will probably have to answer this) is a plastic gear that drives one of the heater/AC/defroster gates has stripped it’s gears and the electronics keeps trying to make it open or close. Finally it either gives up or manages to get the gate open or closed.
Try changing the heater/AC/defroster controls to see if you can repeat the noise.
edit: VDC: you were answering this at the same time I was…