What was found
ON RUN-UP, THE YAW SAS AND BACKUP SAS CAUTIONS WOULD NOT EXTINGUISH. AVIONICS WAS ABLE TO GET THEM TO TURN OFF. AFTER TAKEOFF THE ACTUATOR CAUTION ILLUMINATED AND DID NOT EXTINGUISH. 0 VDC PRESENT AT AFCS CONNECTOR J75537 PIN 17; INDICATING YAW SEMA REQUIRES REPLACEMENT IAW AMM 22-10-00, 5-1 & WDM 22-12-00-000. CAD INDICATES ACTUATOR FAILURE AND AN AMBER Y ON PFD. REMOVED AND REPLACED YAW SEMA ACTUATOR IAW AMM 67-20-00, 4-8 & AMM 67-20-00, 4-14.