As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ACFT PERFORMED AN AIR TURN BACK TO DEPARTURE AFTER DETECTING AN ACRID, BURNING ELECTRICAL ODOR IN THE COCKPIT. NO VISIBLE SMOKE IN COCKPIT, BUT ODOR WAS STILL PRESENT AFTER RETURNING TO THE GATE. MAINTENANCE FOUND THE LEFT WING LANDING LIGHT SWITCH S1-5 BURNED TO BE THE SOURCE OF THE ODOR. THE SWITCH WAS R & R IAW AMM. NO OTHER DISCREPANCIES NOTED, AND THE ACFT WAS RETURNED TO SERVICE.