Originally Posted by sifd4x4

Haha No its not electric. That is a quick disconnect charger. All of our firetrucks and most every newer emergency vehicle have one but im not sure why they decided to put it right there on the fender. It plugs in and is wired to keep things inside the vehicle charged. Such as flashlights, defibrillator, radios, heart monitors, etc. They may also have that one wired to a block heater but other than that it has nothing to do with the motor. The plug-in is also spring loaded so that when you crank the vehicle it will pop out and you dont have to worry about unplugging it.