What must you remember when coupling up a trailer?

When coupling a trailer, it's important to follow the correct procedure for connecting the brake hoses. First, you should connect the service line, which is the yellow hose coupler, to make sure the trailer's braking system is ready for use. If the hose couplers are combined into one unit, you can connect both the service and emergency lines at the same time. Connecting the service line first ensures that you can control the brakes properly during the coupling process. Remember, connecting the emergency line (the red hose) first is incorrect, as it could release the trailer brakes before the system is fully secure. Always start with the service line or both at once if a combined coupler is present. This sequence ensures safety and proper trailer operation.