As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEVEL 3 AIR MANIFOLD 1 FAIL AT FL 370. BLEED & PACK CONFIGURATION AT TIME OF FAILURE WAS NR 1 & 2 BLEEDS & PACKS ON. NR 3 BLEED & PACK OFF & 1 - 3 ISOL VLV OPEN. AFTER RUNNING QRH PROCEDURES THE NR 1 MANIFOLD SHOWED RED ON AIR SYNOPTIC FOR 10 - 15 MINUTES. FOUND LT WING DIFFERENTIAL PRESSURE SWITCH INDICATOR TRIPPED IN CAC. R & R LT WING DIFFERENTIAL PRESS SWITCH IAW MM 36-23-03-4. OPERATIONS TEST PERFORMED IAW 36-23-03-5. OPERATIONS CHECKED NORMAL. ACFT OK FOR SERVICE. IAW GMM 12-7-600 SDR PART INFO, WING MANIFOLD FAIL DET SWITCH.