How do you add refrigerant to a 1994 Buick Century?

To add refrigerant to a 1994 Buick Century, first locate the low-pressure service port, which is typically found on the larger A/C line. Ensure the engine is running and the A/C is set to the maximum cold setting. Attach the refrigerant can's hose to the low-pressure port and slowly add refrigerant, monitoring the pressure gauge to avoid overfilling. Always consult the vehicle's manual for the specific refrigerant type and capacity, and consider wearing safety gear while performing this task.