We have owned this 1993 Mercury Grand Marqis since new. MANY times the power windows have ceased to work. Usually the problem is because the three plastic drive pellets inside the gearmotors have descintigrated. Obviously due to improper selection of materials in the original design, and even continuing into the replacement parts..... and/or improper selection of the lubricant therein which may be acting as a stress-crack promoter on that particular plastic. Sometimes we went to the dealer, who overcharged for replacing a motor and then when I had to replace it later myself, found markings on it to indicate it had come from a local cheap Auto Parts store as a rebuilt, rather than the new FoMoCo part we had paid for. In any event, even those cheap replacement parts used the same poorly chosen plastic parts. I solved the problem myself by machining some Delrin replacement pellets and have had no trouble with them.