Where do you put the freon in on a 1999 buick regal?

The low-pressure port for adding refrigerant (freon) to a 1999 Buick Regal's air conditioning system is usually a blue cap located on one of the AC lines near the firewall or condenser. However, you should not attempt to add refrigerant yourself.

Adding refrigerant requires specialized equipment to measure the system's pressure and vacuum, and to ensure there are no leaks. Improperly adding refrigerant can damage the compressor and other components of the AC system, leading to costly repairs.

Take your car to a qualified mechanic or AC specialist for proper diagnosis and repair of your air conditioning system. They have the necessary tools and expertise to identify the problem (which may not simply be a lack of refrigerant) and fix it safely and effectively.