Thumping sound

[mrnapolean1]

I got a 91 chevy that makes a random thumping sound when the key is turned.
It sounds like its coming from the blower motor (or somewhere in that area).

It occurs after you turn the key off and stops shortly after.

How do I fix this?

EDIT:
Heres a video where the thumping sound is coming from.
https://www.youtube.com/watch?v=JFTS8ZmVXkU

A bottlecap has provided temporary silence but I want to fix it right.

 

[someotherguy]

Seems to be getting asked a lot lately.

http://www.chevytalk.org/fusionbb/showtopic.php?tid/170970

Richard

 

[mrnapolean1]

Ill have to give this a try.

 

[mrnapolean1]

Did some more troubleshooting and its not nowhere near that actuator.
I did a video on wheres the noise is coming from....
Ill post as it becomes available....

It is that actuator. I didn't see it behind the blower box on my initial diagnosis.