What was found
AFTER APP MODE ENGAGED ON ILS 16R, SINGLE CHANNEL BLINKED, APP MODE DISENGAGED. G.S. STAYED ACTIVE. LOC/VOR MODE WENT BACK TO ARRMED. APP BUTTON NON RESPONSIVE. GROUNDED - YES. DFCS CHANNEL A&B SHOWED NO RELATED FAULTS LAST FLIGHT, HGS COMPUTER SHOWED NO FAULTS LAST FLT. PERFORMED W/NAV 4000 (IFR) TESTER ILS LOC/GS TESTS. PERFORMED DFGS CURRENT STATUS AND LAND VERIFY TESTS W/ NO FAULTS. ALL TESTS GOOD. NO HISTORY LAST 90 DAYS ATA 22, 34 AND 27.