As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: ON ROTATION FROM LAS, MASTER CAUTION FLT CONT ILLUMINATED. ON THE OVERHEAD PANEL NO FLT CONT LIGHTS ASSOCIATED WERE ILLUMINATED.WITH NO OTHER INFORMATION, QRH PROCEDURE WAS UNABLE TO BE USED. WITH A CALL TO MOC IT WAS DETERMINED THAT THE FAULT WAS UNABLETO BE DIAGNOSED CAUSING A DIVERT TO PHX. MAINTENANCE REPLACED PRESSURE SWITCH S00141.