My 84 was the same gen as 85 and the shop manual confirms what I remember
(US market). Although I sold the car 15 yrs ago, I still have the shop
manual.

The motor is up front in the headliner (above the round plug, just behind
the mirror mount).  In order to remove the motor:
1. Remove the headliner (sunvisors, rear view mirror and base, front pillar
garnishes, interior light, quarter window trim - each with their own
detailed manual sections!)
2. Remove the rear roof trim and clips then the roof lining.
3. Remove the motor by removing the 2 bolts and 3 nuts from the motor mount
plate.
4. Disconnect the wire harness at the connector and remove the motor.

Before going to that trouble, what troubleshooting have you done?
1. Does the motor even try to move?
2. There's a clutch adjusting nut (cw to increase force, ccw to decrease)
which you might be able to see through that round headliner plug.
3. Wasn't there a thin bent angled wrench for emergency use on that sunroof
motor? If so, turning slightly might help "unstick" the motor (but not while
the key is on or it might start spinning on you).
4. There's a 35A sunroof fuse in the underhood fuse box (looks to be screwed
down near the middle of the box, above the 65A main fuse), and 2 sunroof
relays (open & close) in the same box. Then there's always the dash switch
that could be bad too (less likely).

Testing the motor once the connector is disconnected is simply to apply 12 v
to the 2 pin motor connector, then reverse the leads to ensure it runs in
both directions. Of course this probably means the headliner has to be
removed first.

J.