Hoping you can help me here

Hoping you can help me here. Rear left electric window will not go up. Some months ago it would not function when pressing button on door itself but the button in the front console worked fine. Kiddy lock not a factor. Yesterday it stuck down again and I pulled it up manually and everything okay. My son borrowed the car today and put all windows down from front console and later all came back up except the rear left again. I have tried to manually lift it up but it appears to be firmly stopped in the position it is currently in which is about a quarter way up. Hate to ask but my airconditioner keeps cutting in and out expecially when accelerating it cuts off and when cruising it works fine.