As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSTALLED NEW WCU AT POSITION 13.1 PER AMM UP TO STEP 1.D. REQUIRES SOFTWARE UPDATE AND INSTALLATION TEST DUE TO REPLACEMENT. PERFORMED SOFTWARE UPDATE AND INSTALLATION TESTS OF WELS SYSTEM DUE TO WCU 13.1 INSTALLATION REF AMM 33-51-07-01A-720A STEPS 1.D TO END. ALL TESTS PASSED. EMERGENCY LIGHTS OPS CHECK GOOD AT THIS TIME.