As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB OUT, FAULT CODE 52-34-XB-00, MAIN CARGO DOOR LIGHT ILLUMINATED. THE CREW RETURNED TO DEPARTURE WITHOUT FURTHER INCIDENT. MX TROUBLESHOT MAIN CARGO DOOR SYS AND FOUND LOCK BAR SWITCH OUT OF ADJUSTMENT. THEY ADJUSTED LOCK BAR SWITCH IAW IAI MM SUPPLEMENT 52-71-09 PAGE 205. OPS CHECK GOOD IAW IAI MM SUPPLEMENT 52-32-00. ACFT WAS RETURNED TO SERVICE.