What was found
AIRCRAFT WAS GROUNDED: ON DEPARTURE FROM DFW, AFTER ACTUATING THE GEAR HANDLE, A GEAR DISAGREEMENT CONDITION OCCURRED WITH THE GEAR REMAINING EXTENDED. QRH PROCEDURE FOR GEAR DISAGREEMENT ACTIONED. GEAR RETRACTED AND NO FURTHER INCIDENT. BE ADVISED THAT THE MANUAL RELEASE DOOR APPEARED TO BE FULLY CLOSED AND NO MANUAL GEAR EXTENSION ACCESS DOOR LIGHT WAS NOTICED BEFORE OPENING. POSSIBLE MICROSWITCH ISSUE. INSPECTED LANDING GEAR MANUAL EXTENSION ACCESS DOOR SWITCH AND FOUND EXCESSIVE DUST AND DEBRISES, CLEANED AFFECTED AREA, NO DAMAGES NOTED, ACCOMPLISHED ALTERNATE LANDING GEAR MANUAL EXTENSION SYSTEM TEST A/C NOT ON JACKS, PER AMM 32-35-00-730-802 AND 32-34-00-730-802. ALSO ACCOMPLISHED ALTERNATE LANDING GEAR TEST, PER AMM 32-31-51-400-801-G, CYCLED LANDING GEAR THREE TIMES OPERATIONAL CHECKED GOOD.