My 2009 Dodge Ram 1500 was making a knocking sound whenever starting it.
You can here what it sounded like here:
In doing a search on the problem I found this video that was extremely helpful:
His dash is a little different from mine since he has the Laramie Edition.
The part that went bad is the Blend Door Actuator. I got the replacement part from my local Dodge dealer. Some folks seem to think there is a recall on this but for $50 I figured it was easier just to do it myself and not spend a bunch of time with the dealership.
I shot this video since the actuator in my truck was accessed differently.
Hopefully this can help someone else save some time and money on this very easy repair.
Post time: Sep-23-2017