What was found
DUAL AUTO PRESSURIZATION FAILURE. ACFT GROUNDED. TROUBLESHOT, FOUND CPC-PNL WIRING FAULT ON PRESSURE CONTROLLERS. REMOVED CABIN PRESSURE CONTROLLER 1 AND CABIN PRESSURE CONTROL MODULE REF AMM 21-31-01 AND 21-31-02. ALL WIRING CONTINUITY CHECKS PASSED, EXCEPT PIN 18 TO GROUND ON CONNECTOR D10726. REMOVED WIRE 5509-20 AT GD506, WIRE CHECKS GOOD. REINSERT WIRE 5509-20 INTO GD506. PIN 18 AT CONNECTOR D10726 CONTINUITY CHECKS TO GROUND, REF WDM 21-31-23. REINSTALLED CABIN PRESSURE CONTROLLER 1 REF AMM 21-31-01. REINSTALLED CABIN PRESSURE CONTROL MODULE REF AMM 21-31-02. PERFORMED OPS TEST, OPS TEST NORMAL REF AMM 21-31-01 AND 21-31-02. INSTALLED NR 2 CABIN PRESSURE CONTROLLER. OPS CK GOOD REF AMM 21-31-01