Dennet doesn't know that he doesn't belief in consciousness. But he doesn't believe in qualia. I interpret that as not believing in consciousness. And, the way he tries to explain consciousness indicates that he thinks that if you explain a system's input-output behavior, you've explained everything about the system. This also implies that there is no phenomena other than input-output to be explained; this implies there is no such thing as consciousness.

(Asking what a philosopher "believes" is a tricky question, since analysis usually show many important propositions that their writings imply both belief and disbelief of. This applies to all people, of course; it's just more problematic in philosophers.)

If you want to understand how someone can hold the positions they do, you will have to understand that they are not confusing cognition, action or perception with consciousness.

My point is that they are. They think that explaining the perception, cognition, and action is all they need to worry about, and all else is mysticism.