Your vehicle pulls to one side when braking.
When you brake you hear a squealing or grinding noise.
When you press your brake pedal the pedal pulsates up and down. It may also feel squishy/unreactive.
You are pushing the brake pedal with much more force than usual for the same braking result.
If your brake light is on, and it is not a normal malfunction. It is a sign to come in and have your brakes checked.