What is the purpose of the electrical cord connected between the tractor and trailer?
a.To charge the trailer battery for the refrigeration unit
b.To provide power for the trailer lights including brake, turn, and running lights
c.To power the trailer brakes
d.To connect the radio system
Explanation
The electrical cord provides power from the tractor to the trailer for all lighting, including brake lights, turn signals, clearance lights, and running lights. Without it, other drivers cannot see the trailer signals, creating a serious safety hazard.