As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CROSSFEED OPERATION #1 LOW PRESSURE LIGHT DID NOT ILLUMINATE WHEN OFF SELECTED. LIGHT DOES WORK WHEN LIGHTS TEST COMPLETE & PUSH TO TEST. GROUNDED - YES. REPLACED #1 AFT LOW PRESSURE SWITCH PER B737-900 AMM 28-42-11. OPS CHECKED PER AMM 28-22-41. #1 LOW PRESSURE SWITCH ILLUMINATES WHEN SELECTED OFF AND DURING CROSSFEED OPERATION. OPS CHECK GOOD.