Seems you are having to go deeper than I had too.

If the switches and relays are being good boys most of the time this makes for an intermittent problem. I hate intermittent problems too.

Just for your thoughts, I like blaming crusty ground points. Since there are two motors involved it might be a central grounding connection that wakes up. Trouble is, they are like me and those sleepy moments are going to get longer, the older they get!

Maybe some one like Art Bienstein has a magic diagram that will point those out to you!
The doors are hinged so there has to be a grounding wire to make for better grounds.

Believe it or not the insides of doors are no where near water resistant. If you open the panels,clean the bottoms of the inside and the drain openings out. Built up moisture in there affects the mechanics, electrical, speakers and the "automotive world" truly expensive, plastic protected pressed hardboard panels.

A side note and nothing to do with the doors. The rocker panel or thresholds need to be cleaned of leaves and twigs every few years. They get in from the windshield cowling vents. There is a plastic plug, under the carpets outer edges of the foot wheel area, that you can pull out for inspection. You will need a mirror, flashlight, a narrow vacuum nozzle or some gripping cable type retrievers to get them out.

Phil