As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TEMP INDICATION IN BOTH FWD & AFT SUPPLY DUCT NOT CORRECT. WITH NORMAL TEMPS IN CABIN, FWD INDICATES 14'C,AFT INDICATES 6'C. GROUNDED - YES. FOUND P5 OVER HEAD PANEL GROUND STRAP NOT SECURED, SECURED SAME GROUND STRAP REF. SWPM 20-20-10. CABIN TEMP INDICATION NOW READS NORMAL REF B737-800 AMM 21-61-32 W/ COMPARISON USING DIGITAL THERMOMETER. RAN BOTH PACKS, SUPPLY DUCT TEMPS MATCH CABIN TEMPS REF. 21-61-00. GROUND VERIFICATION TEST GOOD.