What was found
DURING TAXI AFTER STARTING ENGINES AFT CARGO DOOR LIGHT ILLUMINATED EICAS MESSAGE,CARGO DOOR LIGHT INDICATOR WAS LOOSE NOT ILLUMINATING. A/C RETURNED TO THE GATE (BTB) AND MTX GROUNDED A/C . MTX PERFORMED DVI OF CARGO DOOR PROX. SENSORS NO DEFECTS NOTED CYCLED AFT CARGO DOOR OPS CHECK GOOD NO DEFECTS NOTED. RESET INDICATOR. OPS CHECK GOOD IAW AMM 52-00-00 AND 33-00-00 . ACFT OK FOR SERVICE .