vibrologist wrote:What is the noise? Tuck-tuck -tuck....?
If it is clicking like that you need a new recirculation actuator. I did this just a few weeks ago.
Does it go away or come back when you engage or disengage the circulation button? If so, Vibrologist is spot on.
Otherwise, it could simply be debris in the blower motor. If you haven't changed the cabin air filter in a while, now is as good of a time as any to do so while checking on the motor.