Good morning and thanks for the reply. I waited to reply till now so I would have a chance to listen more closely to the sound and the location it coming from. I can only hear it once the car is shut off...key in off position or removed. It's coming from behind and below where the temp controls are located....I'm sure its in that specific area. It seems to me like the unit is hunting for rest position once shut off. Kinda like the older vacuum controlled units....this isn't vacuum controlled is it?? So in answer to your questions I'm sure its not critters....and its location is more centered than one side or the other.....like I mentioned I can only hear it when the HVAC is off with the power in the car off. Thanks again for your help on this.