As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) HEATER OVERHEAT SWITCH POPPED. INVESTIGATION FOUND PILOT HAD PULLED HEATER DOOR OPEN, BUT THE CABLE WAS STIFF AND THE CABLE BRACKET BROKEN. THE RESULT WAS THE HANDLE TOOK OUT THE PLAY GIVING THE IMPRESSION THE DOOR WAS OPEN. THE SUBMITTER REMARKED THAT THERE IS NO BRACKET SHOWING IN THE I.P.C.