'97 Ford Expedition XLT: Every now & then the door lock(s) go "nuts", it seems they are trying to "cycle", the knobs don't go up nor down but a "cycling" sound occurs in one or more of the door locks. Recently, all doors were doing it and I couldn't' manually unlock any of them. After a while, it stops and everything is OK.

wet switch or keypad for keyless entry? Problem with your remote(s) ? Wet inside ? Try to show it to the Ford service drive guys when acting up, or explain. They can search TSB's if they are unfamiliar. If it drives you nutty, you can unplug the master switch, but you have to get the thing up and out for access. see what they say.

spills into unlock switches can cause unwanted connections. then it dries, and... ? External key pads that are wet leaking in can have intermittant unexpected trippy flip. (some say, gem issues) wait for diagnosis. gem module. receiver antenna issues or harness chafing. TSB or SSM can be found but age of vehicle makes it not current. They keep the books for a long time, but ?

TSB and SSM are engineering discussions and fixes for known issues. They save time and prevent unnecessary part replacing. once you get their info, you can decide if you need to invest in a truck that many years old. a heater placed in the truck can help dry things if you have issues with the damp.