obviously there is one, its the force driving the typing of these words. It isn't the machinery typing them but the fundamental quality of the machinery that feels like it does.
Of course I can't prove my consciousness to you, but I operate on the assumption that p-zombies are nonsense, so, it should be entirely possible to prove your consciousness to yourself, albeit difficult due to lack of meaningful language labels for subjective experiences.
(We do have meaningful language for subjective experiences - we call eggplant "purple" and sugar "sweet" and music "groovy" - these correspond not to any physical property, but how they influence our minds.)
I have subjective experience, including the subjective experience of observing my own behavior. So do you. The redness of a tomato has to look like something, and furthermore has had to evolve to catch the attention of animals like yourself that would be nourished by it. Meanwhile, animals like yourself have needed to evolve to find red things appealing. No mysteries there.
Anything that can perceive itself and can perceive itself perceiving will exhibit all the hallmarks of what we call consciousness. It's a recognizable behavior pattern with a name. Imagining there is more to it than that is just tying yourself in knots to no purpose.
In my opinion this just delays the question. The question now becomes whether machines can perceive themselves (or really anything at all) or whether they can just mechanically and symbolically represent the perception of objects, including themselves. If the answer is yes, then that implies that any sufficiently large representation of computation has a consciousness and therefore that there is nothing special about it. If it is no, then where's the relevant difference to a human brain?
I have no reason to think that you are not mechanically and symbolically representing the perception of objects and events. A pattern of activation of neurons is a symbol.
You might as well talk about the mystery of where the execution comes from, when the program starts, and of where it has gone when the program finishes.