As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT AIR RETURN DUE TO L1 DOOR OPEN INDICATION AFTER TAKE OFF DURING CLIMB AT 8,000 FT. CREW FOLLOWED QRH, DECLARED AN EMERGENCY AND RETURNED TO DEPARTURE. MX FOUND DISCREPANT HARNESS PINCHED. DOOR SENSOR ELECTRICAL HARNESS WAS REPLACED. OPS CHECKED GOOD.