I am hearing a low pitched "whom whom whom" when my air conditioner is set to low. If I turn it up from low the blower is loud enough to cancel out the noise. Any ideas?
Probably the blower motor fan blades need cleaning.
Slide under the dash from the passenger side and disconnect the wire plug, Remove 3 mounting bolts and take the blower motor out. Wear goggles as dust particles can fall from the unit.