Which of the following is NOT a cause of vehicle fires?

Excessive fuel consumption is not a direct cause of vehicle fires. While high fuel consumption can indicate engine inefficiency or mechanical problems, it does not inherently lead to combustion or fire. Fires generally stem from situations where there is a source of ignition combined with flammable materials, such as fuel leaks or electrical failures.

On the other hand, under-inflated tires can generate excessive heat during operation, which may contribute to tire failure or ignition if they become too hot and come into contact with flammable materials. Short circuits due to damaged insulation can create sparks and heat, leading to fires, especially if they occur in areas where flammable materials are present. Loose connections in the electrical system can also lead to arcing or overheating, creating a fire hazard. Therefore, while the other options are directly linked to the potential for vehicle fires, excessive fuel consumption does not pose the same risk.