As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSTALLED OVERHAULED STEERING VALVE ASSY. 20 HOURS LATER, STEERING VALVE FAILED. TROUBLESHOT, FOUND BAD PRESSURE SWITCH. INSTALLED NEW PRESSURE SWITCH AND STEERING WAS STILL INOPERABLE. FOUND SWITCH WAS LOOSING CONTACT WHEN SWITCH WAS DEPRESSED ALL THE WAY. INSTALLED ANOTHER PRESSURE SWITCH FOR STEERING VALVE ASSY. PERFORMED OPERATIONAL AND CHECKED SATISFACTORY.