What was found
LDG GEAR INOP CAUTION ILLUMINATED AFTER NORMAL GEAR RETRACTION. AMBER GEAR HANDLE LIGHT ILLUMINATED. RETURNED TO FIELD. LANDING UNEVENTFUL. REMOVED FROM SERVICE. INTERROGATED PSEU AT GATE AFTER A/C RETURN AND FOUND "NGLK 2 FAULT PROX SENS OPEN" MESSAGE IN CURRENT FAULTS. REMOVED NLG ALT LOCK (NGLK2) ELEC HARNESS IAW AMM 32-21-11-000-801 & REPLACED HARNESS IAW AMM 32-21-11-400-801 STEPS 1 THRU 3 4B (15) (A) THRU (Q) AND 5. OPS TEST OF LANDING GEAR PRIMARY EXTENSION & RETRACTION IS GOOD IAW AMM TASK 32-31-00-710-801. RETURNED TO SERVICE.