What was found
AFTER ENGINE SHUTDOWN AT THE GATE, A RED BOX SHOWED ON THE NR 2 EGT. ACFT GROUNDED. ACCOMPLISHED A NR 2 ENGINE EGT CONNECTOR CLEANING IAW AMM 77-21-00-140-801. PRE-CLEANED TEMPS WERE S1-153, S2-113, S3-112, S4-146. POST-CLEANED TEMPS WERE S1-31, S2-17, S3-17, S4- 30. ACCOMPLISHED T49.5 PROBE AND EGT SYSTEM INSPECTION IAW AMM 77-21-01-200-801-F00 AND FOUND A SHORT TO GROUND IN THE CJ9 HARNESS SECTION FOR THE S4 PROBE. REMOVED AND REPLACED THE CJ9 HARNESS IAW AMM 73-21-06 AND OPS CHECKS GOOD IAW AMM 73-21-00-700-802-F00.