How do I repair the stop/break sensor on my 2000 Montero Sport suv located by the shift/gears

My SUV is having difficulties starting the engine sometimes just hear a click but when I
move the gear handle back a forth, a bit then it starts. I was told that I may need to clean
or replace the brake senior located at the center where I shift the gears, is this true? if yes
how do I remove the cover to get to the sensor and clean it or replace it? Thank you,
Costas