What was found
AMBER TAIL LIGHT ILLUMINATED ON UPPER DISPLAY UNIT ABOVE RT ENGINE INDICATORS AFTER BOTH ENGINE ANTI-ICE SWITCHES WERE TURNED ON. ALSO, RT COWL ANTI-ICE BLUE LIGHT WAS ILLUMINATED BRIGHT. CYCLED RT ANTI ICE SWITCH AND ALL INDICATORS WERE NORMAL. ACFT GROUNDED. ACCOMPLISHED ENGINE COWL ANTI-ICING OPS TEST IAW AMM 30-21-00-710-801 SUBTASK, 12, OVERPRESSURE DETECTION CIRCUIT TEST. OPS CHECKED GOOD. NO RELATED CDS OR ENGINE FAULTS. COMPLETED ENGINE COWL ANTI-ICING OPS TEST IAW AMM 30-12-00-710-801. TEST PASSED. NO DEFECTS NOTED. ACCOMPLISHED FIM TASK 30-21 TASK 805 WITH NO DEFECTS FOUND. DETERMINED TO BE AN INTERMITTENT FAULT. NO HISTORY PAST 90 DAYS. OK FOR CONTINUED SERVICE.