No power

Very unusual for NO power...so you are saying the windows and locks do not work....they all have separate power sources. So it could be a bad ground which they all probably share.

The weight of the door will eventually cause it to start sagging, and the electrical contacts won't hit correctly. Try pulling up on your door as you close it. If it works, you'll know that the issue is the bushings in the door hinge.

I have an 2007 Lucerne and I had the same problem. I hate to tell you this but the wires in the door harness, inside the rubber flexible tubing probably are cracked and broken. This happens over the years of opening & closing the door. You’ll need to pull back the harness, find the broken wire or wires, cut and splice new ones in, then you’ll restore power to the door controls. This also happen on a 96 Century I had. Retired mech. of 34 years.