Q: Brakes randomly locking up.

Hi there. Your ABS system should keep the brake from locking up if it is working properly. With that being said, you may get different wheels braking at different times if the ABS unit sees the need to cycle the brakes at each wheel for better and safer braking. Some people feel like this is the brakes locking up. If the brakes are indeed locking up then there is a malfunction. If the ABS light is on then the system is turned off by the computer because of a malfunction. If the light is off then you may have an issue with a failing wheel speed sensor, yaw sensor, or even a mis-matched tire size. To diagnose this a mechanic would need to install a scan tool and monitor the inputs of the sensors to see if one or more of them are acting up. You should get some help from a certified mechanic that has the tools to do this, like one from YourMechanic.