Took the belt out and released the cover on the mechanism side.(Do not open the "springside" tilt the belt back and forth and you can feel the weight moving around). Inside the mechanism is the "movable weight" which is lifting a little arm when the car is accelerating or slowing down. The arm had "jumped" off it's right place and jammed the weight. Just put the arm in it's right place, it's pritty easy to figure out, and the belt worked fine again. It is really a very simple/smart mechanism and worth while looking into.