What does an ABS malfunction indicator light on the trailer usually indicate if it stays on after startup?

Pick an answer

1. A problem with the trailer's ABS system, though the regular brakes should still work
2. That the trailer is not properly coupled to the tractor's fifth wheel at all and needs recoupling
3. That the trailer brakes have been completely disabled
4. That the tires are underinflated

Correct!

Not quite. The correct answer is highlighted.