Diesel fuel leaking when engine is running

Driving home, heard a rattling like a chain dragging the ground. Pulled over didnt find anything. Got home jacked truc up. Spun passenger wheel nothing in the wheel. Took wheel off turned hub. Sound c… 

When I put my Ranger in reverse, there should be a beep to inform me that the sensors are active. This should then be followed by a beeping sound as I get closer to an object. Once close, intermittent… 

Left side beams all good. Right low beam circuit appears dead. Bulb is fine. Books do not show fuses relating to low beam let alone one for each side.

3 lt diesel ranger 2011. Where is heat sensor location. Gauge not picking up