As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN FLIGHT CREW POWERED ACFT UP FOR PRE-FLIGHT CHECKS, A NOISE WAS HEARD BEHIND THE CAPTAINS SEAT AND AN ODOR OF RUBBER WAS DETECTED. MX FOUND THE ZONE TEMP SENSOR FAN BEHIND CAPTAINS SEAT TO BE THE SOURCE OF THE ODOR. SYSTEM WAS DEACTIVATED AT THAT TIME. WHEN ACFT REACHED A MX BASE, THE TEMP SENSOR UNIT WAS CHANGED. OPS CHECKS WERE GOOD AND SYSTEM WAS REACTIVATED. ACFT WAS THEN RELEASED FOR SERVICE.