What was found
AFTER T/O GEAR DOOR OPEN LIGHT INDICATION. CREW FELT VIBRATION FROM OPEN DOORS. PROBABLE CAUSE IS A DOOR OUT OF SEQUENCE CONDITION DUE TO ALTERNATE EXTEND MOTOR NOT RESETTING. THIS IS KNOWN CONDITION AND IS SOMETIMES CAUSED BY DEPRESSING ALTERNATE EXTEND SWITCH FOR A PERIOD LESS THAN 90 SECONDS. WHEN ACTUATED SWITCH MUST BE ENERGIZED FOR AT LEAST 90 SECONDS TO ENSURE THAT MOTOR WILL RESET. PREVIOUS INCIDENTS WERE KNOWN TO OCCUR WHEN MAINTENANCE CREWS USED SWITCH FOR WHEEL WELL ACCESS AND DID NOT RUN FOR THE REQUIRED 90 SECONDS. BOEING ISSUED SERVICE TIP 32-007 ADDRESSING THIS, AND IT HAS BEEN INCORPORATED INTO APPLICABLE SECTIONS OF THE AMM.