What was found
DURING TAXI OUT, FLIGHT 7503, ELECTRIC SMOKE WARNING ANNUNCIATED AND CREW OBSERVED LIGHT SMOKE IN COCKPIT. INSPECTED 80&90VU RACKS, BEHIND INSTRUMENT PANELS, UNDER CENTER CONSOLE, THE PEDESTAL, PITOT, STATIC PROBES, RELAYS AND EQUIPMENT IN 121VU RACK AND GROUND HEAT UNIT. A ENGINE RUN WAS PERFORMED WITH MULTIPLE SYSTEMS OPERATED FOR EXTENDED PERIOD OF TIME NO DISCREPANCIES FOUND. THE AIRCRAFT WAS RETURNED TO SERVICE.