As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOSS OF SOME NAV EQUIPT. FLIGHT DIVERTED. IR 1 SW WAS SHOWING OFF WITH NO ACTION ON SWITCH. SWITCH WAS NOT TURNED OFF BY FLT CREW. IR 1 SWITCH OFF ON ARRIVAL. CHECKED INTEGRITY OF SWITCH. FOUND TO BE POSITIVE WITH GOOD DETENT IN NAV POSITION. CHECKED FUNCTION OF REMAINING SWITCHES AND FOUND SIMILAR ACTION. IRUS ALIGN NORMALLY AND SWITCH STAYED IN DETENT. SWITCHES IN NAV ANC CONFIRMED IN DETENT.