RPM gauge malfunction. how do i fix it? plz help...its my first car...

[AZiaN DriftRaceR X]

ok umm...my rpm gauge is malfunctioning..sumtimes it works...most the time it doesnt!! i checked all the connections at the back of my gauge cluster..and i did a lil snooping around in the engine bay..how would i chek the circuit..and how do i fix it? btw..everything else works fine...except this gauge..thnx 4 all [if any] of your help!