Many, many thanks to jrdubhead and everyone who helped him write this dead-on procedure for replacing the door actuator.
I moved my '01 DTS to Japan four years ago and experienced the dreaded clicking in May of this year. I was pleasantly shocked to find a few lively discussions here when I googled the error code. A quick peek up under the dash confirmed the source of the clicking and gave me confidence that I had identified the right part. I coaxed the actuator to move just one more time to the AC-blow-in-my-face position and pulled the plug from the CB module until I could fix the problem (or until winter, whichever came first).
I got the part from the US two weeks ago, and finally got a chance to tackle the project today.
For me, the most difficult part of the job was cutting the driver's side flared duct. It took about ten minutes, which seemed like an eternity with my feet draped over the driver's headrest. The old CB came off with some moderate persuasion after removing the W module to give me leveraging space, and the new CB went on without a fight when I manually rotated the white flywheel to match its double-d fitting.
I can't imagine how many hundreds of dollars I saved over giving the car to a local mechanic - or worse - to the local dealership.
Thank you all again for saving my bacon.