Postby adnj » April 11th, 2018, 11:15 am
You will have to isolate by disconnecting connectors or fuses to see if the noise is from the electrical control systems. Prado may still be using vacuum controls, you could disconnect those also.
Don't assume that the noise is not coming from a loose bracket or a missing fastener. In my experience, more noise comes from something that is loose, rubbing or lacking lubrication than anything else.
NVH abatement inside the cabin is typically extremely difficult to solve. That's why many luxury cars are sold by the owners after a major collision repair.