My rear power window made a popping noise. It went half way down then stopped. Now it won't move. I took the door panel off. The motor and cable move but the window doesn't. It looks like the plastic window holder is cracked. Do I need a whole new mechanism?

They seem to have a habit of window regulator motors packing up,with ignition on hold the window switch in the down position (if the window is up, hold switch in up position if window already down) with the flat of your hand hit the inner door panel hard, if window then moves it is the motor at fault, if it doesn't move the door panel will have to be removed and the motor bench tested

Are you sure it's the motor and not a wiring issue? Test the motor FIRST. See link below

This is a cable driven window regulator. If you can reach the bolts that attach the glass to the regulator, just remove them and the glass will be free. If you can't reach the bolts, you'll have to cut the cables to free up the glass. Replace the regulator as a single unit.
Test power window regulator Ricks Free Auto Repair Advice

get a new regulator/motor at primechoice.com for $50. When they unravel they are toast.

The cable in the window mechanism (regulator) has broken and wrapped up around the gear on the motor. You will need to replace the regulator/motor assembly.

Three inches at a time, or three inches total? If three inches at a time, you need a power window motor. If three inches total, you need a window regulator. Both these items are typically replaced as an assembly anyway.

Is there any type of noise when pressing/pulling the UP button? If there is any type of electric motor noise, possibly the window regulator is faulty. Pull the door panel off to inspect the motor and regulator.

open the door, make sure the window is in its carrier, power cables conected to the motor and motor is working. This should savd u, good luck.

I have a similar problem with the same window. The window doesn't stop moving but it tilts forward until it won't close properly leaving a 1 inch gap between the top left corner of the window and the door frame from the perspective of sitting in the drivers seat. I had the motor and regulator replaced but to no avail.
I took off the door panel, everything looked fine. Took off all the weather strips and the driver side mirror. Behind the mirror there is the top portion of the metal guide the edge of the window rides up and down. it was partially cracked and bulged out beneath the crack. I gently pounded it back in and cleaned out the guides on both sides with window cleaner and WD-40. The issue will not be completely fixed until I replace the metal guide but it runs much smoother now.

FIRST YOU WILL NEED TO REMOVE THE REAR PASSENGER INTERIOR DOOR COVER TO GET TO THE WINDOW MOTOR. ONCE REMOVED LOOK TO SEE IF THE WIRE IS STILL CONNECTED TO THE MOTOR. IF IT IS, DISCONNECT THE WIRE. ***IF YOU HAVE A MULTIMETER(OR KNOW SOMEONE WHO DOES) WITH THE IGNITION SET TO AUX, OR ON IT DOESNT MATER, TEST THE POWER COMING FROM THE WIRE. IF IT READS 9.5-12+V, THE POWER IS GETTING TO THE WINDOW MOTOR AND STOPPING, YOU NEED A NEW MOTOR. IF THERE IS NO POWER COMING FROM THE WIRE, YOU WILL NEED TO TAKE YOUR CAR TO A SHOP. IT IS NOT A FUSE SINCE ALL THE WINDOWS RUN OFF THE SAME FUSE AND RELAY.

**IF NO MULTIMETER IS AVALIBLE, TAKE A 12V POWER SOURCE (CAR BATTERY) AND RUN THE POWER DIRECTLY FROM THE BATTERY TO THE WINDOW MOTOR. IF THE MOTOR RUNS, BAD WIREING. IF THE MOTOR DOES NOT RUN, BAD MOTOR.

I had the same problem a few years ago except my window was stuck up. There is a cable inside the door that controls the window (not sure what it's called). Anyway, that cable was broken so the motor was working but not the window. Take the door panel off and you should be able to see the cable and if it's still attached correctly.