What was found
ON INITIALLY SETTING POWER (AT APPROX 50%) "STAB OUT OF TRIM" LIGHT ILLUM. (LOW SPEED <10 KTS). WE ABORTED AND DID A CONFIG CHECK - WE RECEIVED A TAKEOFF WARNING. ONCE CLEAR, LT EXTINGUISHED. GROUNDED - YES. DFCS BITE B737-9 DFCS FIM TASK 22-11-00-810-D72.SHOWS NO FAULTS. GVI "STAB OUT OF TRIM" WARNING LIGHT ASSEMBLY LENS WAS LOOSE IN HOUSING. REMOVED LENS CAP ASSEMBLY. NO DEFECT NOTED. EXTENDED CAP AND REPLACED INTO WARNING LIGHTS ASSEMBLY AND CHECKS OK. REF B737-9 AMM 33-11-00-960-803. LENS ASSEMBLY SECURED.