Antilock Braking Systems (ABS)
What ABS does and does not do
ABS prevents wheel lockup during hard braking so you can maintain steering control. It does not shorten stopping distance on all surfaces, and it does not replace safe following distance. On a combination vehicle, ABS may be on the tractor only, the trailer only, or both; the trailer ABS lamp is typically a yellow light on the trailer's left rear or on the dash.
How to use it
When ABS activates, you will feel a vibration or hear a chattering sound. Keep firm, steady pressure on the brake pedal - do not pump the brakes. Pumping defeats the system. If only the tractor has ABS and the trailer does not, the trailer wheels can still lock and cause a jackknife, so the system is not a guarantee.
Traps in questions
- A frequent trap asks whether ABS lets you drive faster or follow closer. No - it only helps you steer while braking hard.
- Another trap: "If the ABS lamp stays on, should you refuse to drive?" The correct answer is that you may drive but should have it serviced; the brakes still work conventionally.
- Questions sometimes ask what to do if the trailer ABS light is on. Check the connection and have it repaired; do not assume the brakes are gone.
Rule of thumb
Stomp and steer - apply firm pressure and steer where you want to go. Never pump ABS brakes.