As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAXI OUT GOT F/O PITOT LIGHT. LIGHT REMAINED ON UNTIL BACK AT GATE. GROUNDED - YES. CKD POWER THROUGH CB HEATERS F/O PITOT - GOOD OPEN CIRCUIT FROM PIN 41 CONNECTOR D638 TO GROUND A. REMOVED F/O PITOT PROBE IAW B737-800 AMM 34-11-01-000-801, FOUND HEATER CIRCUIT IN F/O PITOT PROBE OPEN. INSTALLED NEW PITOT PROBE IAW AMM 34-11-01-400-801. LEAK CHECK OF RIGHT PITOT SYSTEM GOOD. ALL TEST GOOD. REPAIR CONFORMATION ACCOMPLISHED.