This happened once before with the a/c and I bumped the bottom side of the dash on the passenger side and it started back working. I have has the vehicle for 2 years and it has always sounded like jet engines when first started but it winds down after a minute or so, the past few weeks it has been louder and the sound lasts longer. This morning the heat stopped blowing and the bump to the dash did not help. Also #4 setting has never worked. Any ideas or advise? Thank you!