This is an important place to start. I battled a passenger window that would only auto up to a point then go back down. Silicone lube on qtips to the felt the window rides up resolved the issue (after regreasing and swapping out the clips didn’t).What does the window do? Doesn't move at all or is the auto-up / auto-down feature misfunctioning?
OP we need a bit more info to start making proper suggestions.