could also be the switch at the parking brake; maybe it's a little loose, but definitely check your brake fluid level. the yellow light with the circle and hashmarks is for brake pad wear; once the pad gets down to about 1/4 material left it will light up

__________________
1983 300SD (daily driver)
1991 420SEL (work in progress)
1979 300SD (future replacement for 83 SD)

RIP:
1983 300SD (totalled)
1986 420SEL