How can you check that the spring brakes will come on automatically?

To check that the spring brakes will engage automatically, start by ensuring the vehicle is on a level surface and the engine is off. Release the service brakes, and then fully charge the air system to the manufacturer's recommended pressure. Next, turn off the engine and observe if the spring brakes engage by checking for a noticeable change in the brake pedal feel or by inspecting the brake indicators. Lastly, you can also manually pull the spring brake release valve to confirm that the spring brakes are functioning correctly when re-engaged.