As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOTS HEADING SYSTEM CONTINUOUSLY ROTATED COUNTER CLOCKWISE. TROUBLESHOT PROBLEM TO A2S2 IN THE CCU65 CONTROL UNIT. FOUND SPRING INTERNAL TO SWITCH SHORTED TO OPPOSITE TERMINAL. REPLACEMENT OF SWITCH CURED PROBLEM. A HEIGHT QUALITY SWITCH, OR INSULATION AROUND SPRING INSIDE SWITCH WOULD PREVENT FUTURE PROBLEMS. (HEADING SYSTEM WORKED FINE THE DAY BEFORE PROBLEM APPEARED).