As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AUTOPILOT "A" WILL NOT ENGAGE. COULD NOT GET AUTOPILOT "A" TO ENGAGE. PERFORMED DFCS BITE SHOWED MULTIPLE DISCONNECT FAILURES. FOUND F/O'S DISCONNECT SWITCH BAD. THE "A" SIDE OF SWITCH STICKS OPEN REQUIRES NUMEROUS PRESSES OF SWITCH TO CLOSE AND ENGAGE AUTOPILOT. REPLACED F/O'S AUTOPILOT DISCONNECT SWITCH. OPS NORMAL.