Same thing happened to my passenger door window.
Here’s what happened to mine:
There’s a rod shaped kinda’ like a “C” (the ends of the “C” point toward the back of the car) that connects the door latch to the inside of the exterior door handle. The end of the rod that connects to the handle has a grommet that Lexus calls a “Snap-link” holding it to the handle itself. The “Snap-link” deteriorated, broke, and allowed the rod to rotate so that it looked like a “U”. When I lowered the window, it got stuck in the bottom of the “U” but the motor kept pulling down and snapped the plastic part of the window regulator. There’s a guy who shows how to fix the regulator using JB Weld (sorry--I don’t remember where I saw the tutorial) but it looked like he had a lot of the plastic left. Mine was pretty wrecked—I just got a new regulator. Anyway…
Unfortunately, taking the door panel off is the easiest part of the job. The first thing to do is pop out the window/door lock switch assembly. Get a small screwdriver and cover the tip with tape so you don’t scratch the plastic or the upholstery. Then pry up the switch assembly from the end closest to the back of the car. Be careful because if you’re too rough you’ll break the plastic snap holding it in. Then unplug (I’m assuming you know how to operate the connectors so you don’t snap them) the connectors and set the assembly aside. Now take out the door screws; there are 2 screws covered by caps (use the taped screwdriver to get the caps off) on the left side closest to the door hinges, 3 or 4 along the bottom of the door panel, 2 that are underneath the door handle, and 1 under a cover behind the door-open lever(use the taped screwdriver to pop out the cover). When you’ve got them all out, pull the bottom of the door panel toward you (it should pop out relatively easily) and continue pulling the rest of the panel off going from bottom to top. The last thing to do is disconnect the door light connector and the cables that go to the door-open lever and door lock. The door should come free.
