What was found
#1 AND #3 MANF FAIL OVERHEAD LIGHT ILLUMINATED DECENDING THROUGH FL260. SYSTEM CLOSED BLEEDS 1 AND 3 CAUSING AIR SYS 1 AND 3 OFF. CABIN INFO LO ALERT ALSO DISPLAYED. COMPLIED WITH QRH PERFORMED TROUBLE SHOOTING IN REF. TO FIM 36-23-00-2. NO FAULTS ON MANIFOLD FAULT BALL INDICATOR. PERFORMED DECAY CHECKS SEVRAL TIMES ON SYS 1 AND 3 IN REF. TO AMM 36-00-01-5. ALL CHECKS PASSED. NO FAULTS NOTED. REMOVED AND REPLACED MANIFOLD FAILURE DETECTION CONTROLLER PRECAUTIONARY AND PERFORMED R-T-S IN REF TO AMM 32-23-01-5 AND 36-23-01-4. MPN 35008-2. S/N B695 REMOVED. INSTALLED S/N A195. AIRCRAFT OK FOR SERVICE.