Agreed the relay may be performing intermitently. Generally the relay either works or dies completely. More likely is the power window mechanism(s) need cleaned and greased. Old dried grease, dirt/sand and rust will bind up the mechanism's slides, rollers and gears to where the power window will stop moving. This DANGEROUS job is for a person with experience who has worked on power windows before. If you have never done the job before, watch and learn from an experienced person the 1st time around. Note: NEVER put fingers up inside the door to work on power windows. Why? There is a heavy coiled spring in the window mechanism that is under tremendous pressure when the window is in the down position. (The spring aids the window motor to raise the heavy window.) Losening bolts/parts inside the door can release that spring. When that happens all hell breaks loose and there goes finger(s) or hand. This is meant to scare everyone to keep out of there until you know what is involved.
