Hewbie

While driving down the road in my 2006 HHR I've occassionally heard my electronic door locks get a pulse. Doors are locked but there is a secondary (click) happening. Mostly just a partical hit but today a definte full clunk as if I hit the "lock" button on key fob. Then later just the back doors got same "hit !"
Any ideas as to what is happening ?
Sounds like a bad ground somewhere totally random.
Does it signal further electrical happenings ?

thanks, Hewbie

sleeper

Besides hearing, do you see the lock knobs moving ?