During a pre-trip inspection, how do you test that the low air pressure warning activates at the correct point?

Pick an answer

1. Check that the fuel gauge shows a full tank
2. Listen for the horn while the vehicle is parked, which has nothing to do with the low air warning circuit at all, even with the engine running
3. With the engine off and tanks charged, apply and release the brakes repeatedly until the warning triggers at the required pressure
4. Look for cracks in the windshield

Correct!

Not quite. The correct answer is highlighted.