I have had this happen a few times and it has never been a relay, always a fuse. It has always been a fuse because the system is hooked up for the power from the fuse box to feed diagonally. Look in your fuse box and their should be a diagram and it will show you which fuse to change. You can try to rotate the fuse and see if the windows work. Sometimes the fuses are not making a good connection. But if your car has old fuses you need to change all of them...Every 10 years is a guideline. But most of us never know how long if ever our fuses have been changed. I don't think it is a window switch because the power has been split before it gets to the window switches. Try the fuse and if your car does not have a schmatic, then ask and you will be flooded with information...Jim

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James A. Harris