As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HAD A NOSE GEAR DISAGREE WARNING LIGHT AT 18000 FT, RAN THE CHECK LIST AND ALL INDICATIONS WERE NORMAL. NORMAL INDICATIONS PRIOR AS WELL. RETURNED TO DEPARTURE, AND LANDED WITH NORMAL INDICATIONS. REMOVED & REPLACED PS1GA NLG HARNESS IAW AMM 32-61-25, OPS CHECKED GOOD IAW AMM 32-61-00.