What was found
DURING AFTER START CHECKLIST NOTICED DUCT PRESSURE SPLIT WITH LEFT BLEED AIR NEAR ZERO. DISCOVERED LEFT BLEED AIR VALVE C/B POPPED. GROUNDED - YES. ASSOCIATED WORK (REMOVAL AND REPLACEMENT OF MW311 HARNESS ON #1 ENG) ON TSR710969 REF B737-800 AMM 71-51-03. C/B L BLEED AIR VALVE P6-4 A7 COLLAR REMOVED AND RESET; PRSOV OPENED MANUALLY. TEST 7 OF WIRE HARNESS POWER PLANT TEST REFERENCE TABLE NEEDS TO BE ACCOMPLISHED. CONFIRMED CONFIGURATION DEVIATION PROCEDURES REVERSED PRSOV UNLOCKED PER AMM 36-00-00 C/B L BLEED AIR VALVE RESET AND BLEED AIR SWITCH ON #1 ENG ON. RAN AT IDLE AND CONFIRMED BLEED AIR AVAILABLE AND TURNS ON/OFF NORMALLY. PERFORMED TEST FOOTNOTE ITEM *7 EEC TEST PER AMM 71-21-00-700-804 AND TEST PASSED.