As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE ANNUNCIATOR TEST SWITCH WAS ACCIDENTALLY CONTACTED DURING FLIGHT. ANNUNCIATOR TEST SWITCH STUCK IN TEST MODE & WOULD NOT DISENGAGE. ALL ANNUNCIATOR & WARNING LIGHTS REMAINED ON FOR THE DURATION OF THE FLIGHT. AN EMER WAS DECLARED & THE FLIGHT LANDED WITHOUT FURTHER INCIDENT. R & R SWITCH S1-134 TEST SWITCH IAW WDM 33-17-02 & AMM 33-10-00. OPERATIONALLY CHECKED OK. THE ACFT WAS GNDED.