Disclaimer: I did search before asking this question, but nothing I found fit my situation.

I have a 2001 SR5.

The passenger window ONLY works properly when BOTH driver and passenger switch are both up or down at the same time. Never seen anything like that before. We discovered this by playing around.

It has worked fine for many years, just quit working one day.

Already swapped out the passenger window motor and door control panel. Same results. Both switches have to be pressed at the same time.

The only idea we have left is to swap out the drivers switch panel.

All other switches work. Passenger power lock, all drivers switches work (except passenger window control), all other windows work.

Has anybody else seen this before? If the swapping the drivers controls don't work, any suggestions?

If I did miss a thread with someone else having this exact problem, please send it to me.

I had a similar problem on my 97 years ago. Turned out to just be the window switch panel in the driver's door.
It is possible to clean. It's not necessarily made to come apart for cleaning, but it can be done. There are also aftermarket assemblies available, but I can't vouch for the quality of them.

Drivers door "master" switch . . inspect harness at door hinge also