Do you hear the motor trying to move (it is at the bottom of door post where your lap belt is) when you either open your door or turn on the switch? if not, then it may be a blown fuse, check owner's manual. If you do hear it trying to move (you will hear it clicking, there is a thermal overload cutting in and out), then the cable may have freyed and stuck in the track. Is it in the extended position or in the full driving. If in driving position, there is a small round access door at bottom of door post. Open it, there is a tab of cloth tape attached to a wire. Pull it out and disconnect. This will stop the motor from trying to actuate. If it is in the "getting out" position, it may be that the motor has gone bad. You can take an allen wrench and insert it in the whole and wind the seat belt back to driving position. If it will not turn, then the cable is freyed. Go to junk yard and either have the pull a motor/cable for you or remove it yourself if you are inclined. It is not really a hard job, but you do have to have some knowledge of how to take the trim off. The motor should be up to around $100, depends on your area. In the dealership, it will be about $600 just for the part. Take it to a competent mechanic. The cables have a plastic jacket around them, which come apart and jam in the track. The cable cannot be replaced by itself.