The air conditioner on your GMC Envoy cools the passenger cabin by blowing cold air from the A/C compressor through the HVAC vents inside the vehicle. The A/C uses a compressed refrigerant called R134a. If you are having problems with your A/C, the replacement parts and refrigerant for the system are expensive. Before replacing anything or going to a mechanic, first troubleshoot the A/C system.
Open the fuse panel under the steering column on your Envoy by pulling down on the fuse panel with your fingers.
Pull the fuse for the A/C, using the fuse pullers in the fuse panel.
Check the metal strip inside the fuse. If it is blown, replace the fuse with a new fuse of the same amperage.
Start the Envoy's engine and turn the fan speed to the highest setting.
Turn the A/C to the coldest setting. If the A/C compressor does not start, your compressor must be replaced. The compressor will cause the RPMs to temporarily drop when the compressor starts. It will almost sound like the engine is bogging down for a moment. If the A/C compressor starts but there is no cold air, you must have the system recharged with refrigerant by a professional mechanic.
