I can't speak to your experiences, but I personally experience both partial and complete dissociation. Complete being when another alter takes over completely and I am amnesiac for all of their actions and emotions, and partial being when there is some degree of coconsciousness involved. Sometimes with me two or more alters are present together, sometimes one might be watching another from the background, sometimes we might be aware of another parts emotions but not know anything more than that. There are so many different variations and levels of coconsciousness and dissociation for us, with one extreme being no dissociation at all and the other being complete amnesia. In between those two there is a huuuuuuuuuuuuge murky sliding scale of different levels of mutual awareness.
Generally speaking with regards to the overall population of people, dissociation only very, very rarely means complete non-awareness of a dissociated alter state.
Does that help?