CDL Combination Vehicles TestInspecting Combination VehiclesMedium
A driver is conducting a pre-trip inspection of a combination vehicle. They observe that the trailer's electrical connector (pigtail) has frayed wires exposing the copper strands. What is the most significant hazard posed by this condition?
- AOverheating of the trailer's tires.
- BIntermittent or complete failure of trailer lights and ABS.
- CIncreased wear on the tractor's alternator.
- DReduced fuel efficiency due to electrical resistance.
Show answer & explanationAnswer & explanation
Correct answer: B. Intermittent or complete failure of trailer lights and ABS.
Frayed wires with exposed copper strands in the electrical connector create a risk of short circuits or open circuits. This directly impacts the electrical power and signal transmission to the trailer's lights (turn signals, brake lights, running lights) and the Anti-lock Braking System (ABS), leading to their intermittent or complete failure, which is a major safety hazard.
Why the other options are wrong
- A. Overheating tires are typically caused by underinflation, mechanical issues, or brake problems, not frayed electrical wires.
- C. While a short circuit could increase alternator load, the more direct and significant hazard is the loss of critical safety systems on the trailer.
- D. Electrical resistance from frayed wires would have a negligible impact on fuel efficiency.
Trailer Electrical Connector Inspection
Inspecting the trailer's electrical connector (pigtail) ensures proper functioning of lights and ABS by checking for damage, corrosion, or frayed wires.
- Damaged wires can cause shorts or open circuits.
- Affects critical safety systems like lights and ABS.
- Must be securely connected and free from damage.
Memory trick: Frayed wires, no light; safety's plight!