As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE PILOT CHANGED SWITCH POSITION FROM AUTO TO MAX DIFF AND EXPERIENCED LOSS OF BLEED AIR. PILOT WAS ALERTED BY A BLEED OFF MESSAGE, CABIN PRESSURE BEGAN TO DECREASE. INITIATED A DESCENT, RESET BLEED, STABILIZED PRESSURIZATION AND MADE UNEVENTFUL LANDING. WIRING OF THE SWITCH MAY LEAD TO A MOMENTARILY OPEN CIRCUIT DURING THE SWITCH OPERATION. MODIFIED THE WIRING OF THE BLEED AND OVER TEMPERATURE SWITCH IAW SB70-237-01.