As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING PRE-FLIGHT INSPECTION, WHILE IN THE HANGAR, AFTER ENERGIZING ACFT ELECTRICAL SYSTEM, TEMPERATURE CONTROL VALVE COULD BE HEARD OPERATING. FURTHER INVESTIGATION REVEALED THAT THE VALVE WAS NOT PHYSICALLY MOVING, WHILE THE ACTUATOR MOTOR WAS CONTINUOUSLY OPERATING. A SLIGHT TAP OF THE VALVE WOULD MAKE IT STOP. THIS APPARENT INTERNAL LIMIT SWITCH ISSUE COULD BE DUPLICATED. VALVE ASSY REPLACED.