As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, PUT GEAR HANDLE UP AND GEAR SEEMED TO RETRACT NORMALLY BUT LEFT GREEN A LIGHT STAYED ON. CYCLED GEAR HANDLE AND WITH HANDLE DOWN GOT 3 RED B LIGHTS WITH NOSE AND RIGHT MAIN RED A LIGHTS ON CONTINUOUSLY, GEAR WOULD NOT EXTEND AND HYDRAULICS WERE NORMAL. USED ELECTRONIC OVER RIDE PROCEDURE AND RETURNED TO LAX. REPLACED LEFT GEAR A SYSTEM WIRING HARNESS AND BOTH PROX SENSORS. SWUNG GEAR AND OPS CHECKS GOOD.