rear seat belts

i have a 2003 gmc sierra z71 extended cab and the rear seat belt on left side
you cant even pull this thing out to engage it this is a major safety issue any idea what is going on here the truck is out of warranty.or is this a issue that the gm will cover no question.thanks

I had an 88 with the same problem.I had to take the plastic cover off to get in and release it. Try this first, park on a steep hill with the front of the truck uphill. there is a pedulum inside it. Try to pull it out and release it quickly again,worth a try. Don`t expect gm to back anything.