As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: AT CRUISE ALTITUDE, THE LEFT AFT MAIN TANK "LOW PRESSURE" LIGHT ILLUMINATED STEADY. 5.30 QTY INDICATED IN LEFT TANK. RAN QRH AND TURNED OFF THE AFT LEFT PUMP AND "LOW PRESSURE" LIGHT REMAINED ILLUMINATED. FUEL FLOW AND QTY APPEARED NORMAL FOR REMAINDER OFF LIGHT. REMOVED AND REPLACED LEFT TANK AFT PRESSURE SWITCH. OPERTIONAL CHECK GOOD. NO FURTHER DEFECTS NOTED. PER AMM 28-42-11.