In the power distribution box in the engine compartment : fuse # 41 is a 15 amp fuse for HEGO ( Heated Exhaust Gas Oxygen - sensors ) , VMV ( Vapor Management Valve ) , CMS ? and PTEC ( which I believe stands for Powertrain Electronic Controller )
On a 2003 Mercury Mountaineer : In the power distribution box ( which is " live " ) located in the engine compartment on the drivers side : ( # 41 is a 15 amp mini fuse for the HEGO , VMV , CMS , PTEC ) HEGO stands for Heated Exhaust Gas Oxygen ( sensor ) You can view the 2003 Mercury Mountaineer owners manual online at : www . motorcraft service . com ( no spaces ) Click on Owner Guides ( the fuses and relays section starts on page 166 and the power distribution box diagram is on page 171 )