If an Anti-Lock Braking System (ABS) malfunctions: Question If an Anti-Lock Braking System (ABS) malfunctions: Answers The driver will not know. A yellow lamp will light up on the control panel. The brakes will lock up. The brakes will not work. Explanation On a vehicle with ABS, a yellow malfunction lamp on the instrument panel will illuminate to alert you if the braking system is not working. This questions appears in the following tests: Delaware Class A Knowledge Test Georgia Class A Knowledge Test Illinois Double Kansas Class B Knowledge Test Minnesota Class B Knowledge Test New Hampshire Class B Knowledge Test New Hampshire Double North Dakota Double Texas Passenger Utah Class A Knowledge Test