2003 GMC C-Series MK3 Underhood Fuse Box Diagram 2003 GMC C-Series MK3 Underhood Fuse Box Map Fuse Panel Layout Diagram Parts: Anti-Lock Brake System, Engine, Electronic/Automatic Pump, Horn, Powertrain Control Valve, Electronic Control Modul, Powertrain Control Valve, Fuel Pump, Heated Fuel, Ignition, Starter, Horn, Ignition, Power Take-Off, Neutral Start, Rear Defog, Powertrain Control Module, …