What Is This Noise?

[JohnHaggerty]

After the truck is sitting a few days, I hear a electrical actuation type sound when I open the door. I don't always hear this, but it's not the first time. Again, I open the door and hear some type of sound coming from drivers side, forward of the door, below the engine.



What is this?



Thanks!

 

[DonFitzwater]

No clue, but my truck makes the same noise.