It is important to understand the various terminology in Tanya and the proper way of grasping the concepts involved. For this, it is often recommended to appeal to a knowledgeable individual who can make the concepts clear to the student.
In this case, "abode/abides" does not mean so in even the slightest literal sense. It means that the essence of the intellectual power of an individual is what serves as the primary vessel for the GS's dwelling. On the other hand, the coarseness of the heart is the primary vessel for the AS.
Does this negate the fact that either soul can make use of the intellectual or emotional powers of the body? Of course not! It merely points to where their natures lie. Intellect is objective. A person can argue and say, "Well, I disagree! Since I felt it myself!
But a person cannot say "Well, I understood it myself! It sounds silly! The Gdly soul thus dwells "better" in that objective space which allows for Gdliness to be comprehended, since it is not a place which holds of itself any bloated importance.
The coarseness of the person, exemplified by the part of the heart which distributes blood to the rest of the body etc. etc., on the other hand, is an image of ego - what I feel. This is thus where the AS finds its roots - in the "I" exist part of things. A person with this inclination, can of course use his brains - but it will be with a strong interest/subjectiveness towards what HE decides to understand...like those people who use very intellectually-sounding nonsense to excuse their own ideas (but when faced with opposing facts will often cower behind their "logical" ideas as though they were being intellectual).
You get the gist...