2001 SR5

Passenger window will not go up or down unless I press both driver and passenger switch in the same direction at the same time. Basically, both have to be up or down, otherwise it won't work. As soon as I let go of either switch, it quits working.

All other driver panel window switches work fine. Passenger power locks work, just the window switch won't work independently of driver side.

So far I have swapped out the passenger door motor and both driver and passenger switch panels. Problem still exists.

Checked for related fuses but didn't find anything.

No clue what else could be causing it. I searched the forums but couldn't find this problem. If a thread exists with this same situation, please let me know.