Hypothesized Animation of Center Differential Lock Transfer Indicator Switch (Toyota PN #84222-12010 'transfer indicator switch’) for LX470 from 2000 Lexus LX470 Repair Manual
Using the part diagram in the 2000 LX470 repair manual, I hypothesize center differential lock transfer indicator switch movement in this moving illustration in this GIF animation.
Pressing the ball on sensor inwards closes an internal electrical switch. I believe that debris/sludge/contaminants can accumulate behind the ball spring mechanism, interfering with the electrical switch's ability to fully close.

