What was found
EWR - FLT 3512 - FLIGHT CREW REPORTED STRONG BURING SMELL IN COCKPIT. AIRCRAFT AIR RETURNED TO EWR UNEVENTFULLY. MAINTENANCE FOUND C/B TO NORMAL NAV LIGHTS BURNED AND WIRE GOING TO C/B BURNED. REPLACED C/B FOR BEACON NORMAL AND NAV LIGHTS NORMAL POWER SUPPLY. REPAIRED WIRE BETWEEN NAV NORMAL C/B AND LOGO NORMAL C/B IAW ATR-42 WIRING MANUAL AND CHAP 20 STANDARD PRACTICES. OPS CHECKS GOOD, NO ACRID SMELL NOTED. (M)