Class B CDL Practice Test #1

Question #1 of 70

Class B CDL Test Question Image

How can you test the low-pressure warning signal?

There is no way to test a low-pressure warning signal.

Turn the electrical power off and step on and off the brake pedal to reduce air tank pressure. The low air pressure warning signal must come on before the pressure drops to less than 90 psi in the air tank.

Turn the electrical power on and step on and off the brake pedal to increase air tank pressure. The low air pressure warning signal must come on before the pressure increases to more than 60 psi in the air tank.

Turn the electrical power on and step on and off the brake pedal to reduce air tank pressure. The low air pressure warning signal must come on before the pressure drops to less than 60 psi in the air tank.

Turn the electrical power off and step on and off the brake pedal to reduce air tank pressure. The low air pressure warning signal must come on before the pressure drops to less than 30 psi in the air tank.

Class B Commercial Driver’s License

You will need a “Class B” commercial driver’s license if you plan to drive any single vehicle which has a gross vehicle weight rating or gross vehicle weight of 26,001 pounds or more, or any such vehicle towing a vehicle with a gross vehicle weight rating or gross vehicle weight that does not exceed 10,000 pounds.

Source: Federal Motor Carrier Safety Administration.