How do you install freon in a 2006 dts?

To install freon in a 2006 Cadillac DTS, first ensure the vehicle is turned off and parked on a level surface. Locate the low-pressure service port, typically found on the larger of the two AC lines. Connect a refrigerant recharge kit to the port, following the manufacturer's instructions, and start the engine with the AC on high. Slowly add freon while monitoring the pressure gauge until it reaches the recommended level, then disconnect the kit and check for leaks.