How much freon do you put in the air conditioning unit of a 1999 Chevy Suburban 1500?

You can't determine the correct amount of refrigerant (Freon) for a 1999 Chevy Suburban 1500's AC system simply by the year and model. The amount needed depends on the specific system installed in *that particular vehicle*. The amount varies based on factors like the size of the condenser, evaporator, and the specific design of the AC system.

Never attempt to add refrigerant without proper tools and knowledge. Improperly charging an AC system can damage the compressor and other components, leading to costly repairs.

To find the correct amount of refrigerant, you need to:

1. Consult your vehicle's owner's manual: This might list the correct refrigerant type and charge amount. However, this information isn't always included.

2. Check the sticker on the AC unit itself: Sometimes there's a sticker on the AC compressor or another component indicating the correct refrigerant type and charge amount.

3. Use an AC charging system with gauges: A professional AC technician uses gauges to measure the pressure and temperature of the refrigerant in the system. This allows them to determine the correct amount of refrigerant needed based on the system's performance and pressure readings. This is the only reliable way to determine the proper amount.

In short: Take your Suburban to a qualified auto AC technician. They have the tools, knowledge, and experience to safely and correctly charge your system. Attempting to do it yourself is risky and could result in significant damage to your vehicle's AC system.