What was found
CMI - FLT 4374 - ON GROUND IN CMI, FLIGHT CREW REPORTED SMOKE IN COCKPIT, AND ALSO NOTED BOTH AUTO TEMP CONTROLLERS WERE INOP. MAINTENANCE REPLACED COCKPIT TEMP CONTROLLER. GROUND RUN A/C, CABIN TEMP CONTROLLER OPERATES NORMAL IN MANUAL, COCKPIT CONTROLLER CHECKED GOOD BOTH AUTO AND MANUAL AND NOTED NO EVIDENCE OF SMOKE. AIRCRAFT WAS RETURNED TO SERVICE. (M)