Thanks Mike. I am somewhat familiar with this tool. I've seen it in use many times but have never been trained on it.

I'm throwing in the towel on this one as far as fixing it myself. I reckon I'll take out a bank loan for the (probable) DDM replacement and hit the Buick dealer - bite the bullet.

Good luck!
I hope that the dealer can get it working again, without it being too expensive!
Please post back how it goes.

I'm figuring on $400-$600 just for the DDM - then, what..? about 1 or 2 hour'* labor for another $100 or $200.

This one'* gonna hurt.

Well. Guess what..? I accidentally pushed the master LF window switch and the window went down! All the windows and locks and mirrors are now working from the previously dead LF door window switch/module.

It'* got to be temperature related. It was around 95 degrees outside. That was three days ago and they're still working. Hadn't worked all winter and I haven't even tried the switches all summer until I hit it accidentally a few days ago.

I suppose they'll go out again when it cools off around here in a few months. I'm wary of using the windows anyway because they could stop working anytime and I don't want to get stuck with a down window.