hi, i have an '80 450 -- had the same problem --- open up the fuse box, and rotate the fuses for the windows in the holder, to clean them up - if that works, look at the ends of the fuses. they may be indented, causing a poor contact. replace the fuses. or coat the ends with dielectric grease. also, if that fails, you may need to disassemble the power window switches, and clean them. be careful to observe the way the little springs and things are situated in the switch housing -- good luck, pat