Rear seat belt not rewinding

[RoyVernon]

The off-side rear seat belt will not rewind (near side is fine).
These seat belts are only “used” when it goes for its annual MOT; and no one has ever sat in the back of the car from new

Removed most of the lower interior plastic lining, and noticed that there is a yellow electrical connection, which I initially assumed was merely for the in-use/not in-use sensor?
But I wonder if the operation has changed from the good old “days of steam” when this type of seatbelt operated simply off a pair of balancing ball-bearings

The question being, is it stuck merely from lack of use (car’s 5 years old, with 12K on the clock), and possibly an easy fix: or is yet more major internal dismantling to allow replacement

[Percy247]

I believe this is quite a common problem. Does your car have a full Mazda main dealer service history? If so I would approach them and ask for it to be fixed/replaced as a gesture of goodwill. A number of people have resolved the matter this way. As for why it happens? I would love to know?

[RoyVernon]

Hi Percy 247
Thanks for the prompt response

The car does indeed have a full service history registered with Mazda; but not via the local Mazda dealership

Unfortunately, although very conveniently placed, I have found on occasion the end result to be somewhat lacking; and not always a pleasant experience
It is being serviced next week; but elsewhere

However if this is a common problem; then maybe it’s the time to reassess and perhaps cut my losses; and buy something less fragile
Best wishes
RoyVernon

[jtonline]

The electrical connection you've seen will be for the seat belt pre-tensioner. During a collision, sensors trigger an explosive pyrotechnic charge, which in turn moves a concealed piston. Seat belt webbing is wrapped around a spool which is rotated by the movement of the piston. The length of the seatbelt is reduced which removes any slack and tightens the belt. Any repair to/replacement of the seatbelt mechanisms is best left to an expert.