What was found
JUST AFTER T/O, COCKPIT TEMP VERY WARM, W/CONTOL CABIN & FWD IN FULL COLD WERE STILL GETTING 62 DEG C. ON CONT CAB SUPPLY DUCT. CALLED MX CONTROL, ADVISED TO TURN OFF TRIM AIR, PUT CONTROL CABIN & FWD TO MANUAL. FULL COLD FOR 7 MIN = NO CHANGES, 61 DEGREES C, SUPPLY DUCT/LT PACK = 51 DEGREES C. RT=8 DEG C. NORMAL TEMPS IN BACK. B, AFTER 7 MIN, KEPT TRIM AIR OFF & TRIED ALL 3 TEMPS IN AUTO/12'OCLOCK FOR 6 MIN = NO CHANGES LT PACK 51 DEG C, RT 8 DEGREES C. AFTER 1+343 MIN IN FLT, WE TURNED LT PACK, 46 DEG C. OFF W/ALL TEMPS AT 12 O`CLOCK & ISOLATION VALVE IN CLOSED. ALL TEMPS RETURNED TO NORMAL, CABIN ALT STAYED AT 7500 MSL, +35,000MSL CONTINUED TO SEA. ACFT GROUNDED. LT PACK TEMP CONTINUED FAULTS TCV DURING BITE CK IAW FIM 21-62, TASK 801. REPLACED LT TEMP CONTROL VALVE REF AMM 21-51-10-000-801 AND 21-51-10-400-801. OPS CHECK NORMAL.