Assuming that the seat recliner motor is being fed a supply voltage, but is not responding, the most likely scenario is that the commutator segments at the present (stopped) position are contaminated. This happens if the motor is stopped in one position without being used for several months.
To access the motor, the procedure is very much like that to access the "transmission" on the 850 for the seat-recliner that richard describes on his YouTube channel. The difference is that the motor drives the recliner mechanisms directly on the V70. Note that my pictures are taken on reassembly, so the hog-rings that are removed are depicted as plastic tie-wraps; these are a far better way of reassembling the seat. 4.8mm ties, roughly 150mm long are the easiest to work-with (they can be shorter, but it helps to have lots of spare length to aid reattachment of the covers).
The first thing to do is to remove the switch panel and protect the side airbag trigger as described above. It is worth leaving the switch panel plugged back in and resting in the front footwell, as it is necessary to move the seat forwards (if it will move) and raise the rear of the cushion upwards as far as it will go, in order to allow the recliner drive-bar to be extracted through the drivers door aperture.
The next thing is to remove the lumbar support knob and its trim from the seatback. This involves rotating the knob out as far as it will turn, pulling outwards sharply, and then turning further until it will extract from the seat.
The cover for the seat cushion will also need unclipping, as well as the trim for the lower part of the seatback (as richard describes). This is to access the wiring harness for the seat recliner motor, which passes over the front of the tubular cross-beam at the rear of the seat cushion. There are three hog-rings that need to be unclipped (screwdriver turning technique is the best) and the harness itself needs unsecuring from tubular cross-beam;
D5252T_seat_cushion_wiring_clipping.jpg
The cover for the lower part of the seatback has four hog-rings that secure the cover rods for the front/back of the cover together under its base - between the seatback and the cushion.
Unfurl the backrest cover over the plastic pieces that protect the sides of the backrest frame - use two hands to grip the cover down, then roll it over the plastic webs.
Go carefully when unclipping six more hog-rings that secure the front of the backrest cover to the foam at the front of the seatback - the foam will tear-out and leave the cover saggy if you are impatient. Once the cover is unclipped for the height of three sets of hog-rings, there is enough access for the seat recliner motor to be seen;
D5252T_seat_back_components.jpg
The motor is accessed by removing the spring that is circled above, then pulling the plastic seatback trim outwards towards the door aperture (one plastic stub to pull through the metal frame and retain), then a single screw is accessed through the drivers door aperture. The back side of the screw is visible on the picture below, which shows the general arrangement of the motor;
D5252T_seat_back_motor_fitted.jpg
Note that the motor has already been partially-stripped in this picture, as I will explain in the next post.