What was found
PDIS: LEVEL AT FL330, 45 MINUTES INTO FLIGHT, GOT NR 3 MANF LIGHT, FOLLOWED BY A LEVEL 3 "MANIFOLD NR 3 FAIL" ALERT. COMPLIED WITH RED TABS AND LANDED AT NEAREST SUITABLE AIRFIELD (KLAS). MAN LIGHT EXTINGUISHED SOMEWHERE BETWEEN 8000' AND 5000' IN THE DESCENT. FOUND RT WING SWITCH FAULT BALL FAULTED AT PNEU MAN IND BOX IN CENTER ACC COMP. PERFORMED NR 3 PNEUMATIC SYS DECAY CHECK PER MD-10 MM 36-00-02-5 WITH NO DEFECTS NOTED. SUSPECT MAN FAILURE DET PRESSURE SWITCH ON RIGHT SIDE. SWITCH REMOVED AND REPLACED MANIFOLD FAILURE DETECTION CONTROLLER PER REF MM 36-23-86B870.