As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU WILL NOT SHUTOFF WITH APU SWITCH IN OFF. ACFT GROUNDED. INTERMITTENT APU SWITCH, VERIFIED ON APU BITE, INPUT MONITORING PAGE 2/4. APU ON SWITCH AND APU OFF SWITCH BOTH SHOWS, NO, FOR UP TO A MINUTE BEFORE YES SHOWED ON APU OFF SWITCH INPUT. R & R S248 APU MASTER SWITCH REF WDM 49-62-11. INPUT AGREES WITH NEW SWITCH POSITION, OPS CHECKED APU NORMAL.