Help!! 2009 528i rear window wont roll back up
 

We were driving and the driver rear window was partially rolled down, all of a sudden we hear a popping noise, then the window rolls all the way down and has been down ever since. Every time we try to get it back a weird cracking noise occurs and the window wont go back up again, an error message for anti-trap function keeps coming up.. anyone have any idea what we can do, the damn window is completely down and we have no idea how to get it back up.

Sounds like the window regulator failed, certainly very common on E46’s. You will need to remove the interior door card to gain access and install a new regulator. When the rear one failed on my E46 I inserted a piece of wood to the inside of the door to hold the window up until I got the new parts.

Yes he's correct.. your cable or motor snapped inside the door. I would refrain from trying to put it up and down with the motor.. it can only get uglier.. it's a lost cause. If you''ve got a few hands then you could try to grab the lip of the window and pull it way up.. slap some tape on it and then hold it there. Otherwise, you'll definitely have to take the door apart and then try to put a block of wood to hold it. You can buy the whole regulator itself that comes with the cables and motors. I was lucky and figured out what part snapped, and I put it all back together with steel wire/cable.