In my view, consciousness is a gradual thing, not a binary property. In addition, it's also not really "a thing", as in not "something extra". By that I mean, when you make it a habit to probe into your consciousness/awareness, you will find that all there is are perceptions. You may think that you have a qualia about a particular perception (e.g. of a color, a scent, a mood, a memory, an insight, etc.), but then the qualia is only there by virtue of you perceiving the qualia. There is nothing that is pure subject. When you perceive yourself as being a subject (an "I"), it thereby becomes an object of perception. It can't exist without being an object of perception. (E.g. it isn't there when you're unconscious.) That raises the question whether it is really anything more than an object (as opposed to a subject).

Now, a perception in that sense only requires that the thing perceived (the object of perception) has a representation in the brain, plus that some information processing of that representation is occuring in the brain (the act of perceiving). Our objects of perception, including qualia and e.g. the awareness of being conscious, can be very rich and complex, but it's certainly not implausible that they are fully represented in the brain with all their richness — and there is nothing more to it than that representation. (In fact, my personal experience is that the range of qualia is not that large, when you observe it over a longer term and for example compare it to our memory capabilites.)

So, when I introspect my consciousness, I cannot pinpoint anything that doesn't fit that model of "information processing (perceiving) of representations (objects, including qualia)". Even what I think of as "I", in the end, is just one of those objects (or probably more a cluster of those). The confusion, I believe, stems from the fact that we can only introspect a fraction of the information processing that is really going on, and that the "I" as an independent subject is a very strong illusion. But when you try to look closely for it, there is arguably nothing really there. (The Buddhists do have a point with their concept of non-self.)

I think there is a definite distinction between perceptions and models. For example, we don't consciously perceive the edge and motion detection of our vision system but instead the aggregate interpretation of modelling those perceptions. Similarly we don't seem to be conscious of some internal organs, but conscious of others under different circumstances. Usually we aren't conscious of our breath but by focusing we can both raise conscious awareness and control of it. So it seems like we have a "consciousness" module in the brain that can be directed and connected to different other parts of our nervous system, but not all, in order to "do the perceiving". With practice it seems possible to become conscious of more autonomous parts of the body, but not all.

And still the question remains of how the brain produces the conscious experience and expands or contracts it, while not being fully conscious of the whole brain or of its own operation (in which case we would understand consciousness much better). Is it the chemical activity? The electrical? A combination? Is it in the energy transfers between matter or in the relationships that get established?