As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF AND GEAR RETRACTION, THE LEFT RED GEAR DISAGREEMENT LIGHT REMAINED ILLUMINATED. CYCLED GEAR HANDLE DOWN AND UP, IAW QRH AND LIGHT STILL ILLUMINATED. PERFORMED A CHECK OF THE LEFT GEAR UP AND LATCHED SENSOR PER MM 32-60-05. INSPECTED SENSOR AND ASSOCIATED WIRING. NO DEFAULTS NOTED. PERFORMED A PROXIMITY BOX TEST IAW MM 32-60-04. SYSTEM OPS CHECKED GOOD. AIRCRAFT WAS GROUNDED.