What was found
CREW REPORTS WHILE TAXIING OUT FOR TAKEOFF, SMOKE AND FUMES CAME OUT FROM BEHIND THE CENTER PEDESTAL LIGHT CONTROL UNIT. PULLED APPLICABLE CIRCUIT BREAKERS, THE SMOKE STOPPED. RETURNED TO GATE AT DFW. MAINTENANCE CONTROL DEFERRED LIGHTING SYSTEM, A/C RETURNED TO MKE. MAINTENANCE REPLACED CENTER INSTRUMENT PANEL AND PEDESTAL LIGHT CONTROL UNIT. OPS CHECK GOOD, RETURNED A/C TO SERVICE.