What was found
DURING DESCENT THRU 18000 FEET WITH WING AND ANTI-ICE ON, AN AMBER LEFT BLEED AIR HOT CAS MESSAGE ILLUMINATED. THE HIGHEST TEMPERATURE SEEN AS LIGHT EXTINGUISHED WAS 522F. THE LIGHT WENT OUT AND THEN CAN BACK ON. THE LIGHT EXTINGUISHED AGAIN AND NEVER CAME BACK ON. THE FLIGHT ATTENDANT REPORTED A MOMENTARY BURNING ODOR IN THE BAGGAGE AREA. REMOVED LEFT FAN AIR VALVE AND INSTALLED A REPAIRED VALVE OPS & LEAK CHECKED GOOD. IAW MM 36-14-01. OPERATIONAL CHECK DONE IAW MM 36-12-00.