How do you add freon in a Cadillac dts?

To add Freon to a Cadillac DTS, first ensure the engine is running and the AC is set to the maximum cool setting. Locate the low-pressure service port, typically found on the larger of the two AC lines. Connect the refrigerant can to the port, following the manufacturer's instructions, and add Freon until the system reaches the proper pressure. Always wear safety goggles and gloves, and consider consulting a professional if you're unsure about the process.