What was found
DURING TAXI OUT, THE NOSE WHEEL STEERING MASTER CAUTION ILLUMINATED AND NOSE WHEEL STEERING WASN'T WORKING. AFTER REFERENCING THE E & A CHECKLIST CAUTION CLEARED. OPTED TO CONTINUE. ON TAKEOFF ROLL, APROX 100KTS, THE NOSE WHEEL STEERING CAUTION ILLUMINATED AGAIN. RETURNED TO DEPARTURE AFTER RUNNING E&A CHECKLIST, CAUTION CLEARED AGAIN. NO ISSUES ON TAXI IN. RETURNED TO FIELD. LANDING UNEVENTFUL. REMOVED FROM SERVICE. FOUND THE P-SWITCH FAULT IN SCU. R & R THE NWS PRESSURE MANIFOLD SWITCH IAW AMM 32-51-16-000-804 AND 32-51-16-400-804. OPS TESTED IAW AMM 32-51-00-710-801, THE TEST PASSED. P-SWITCH FAULT IN SCU NO LONGER SHOWS. NOSEWHEEL STEERING CAUTION DID NOT ILLUMINATE. NO FURTHER DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE.