1. Find the low-pressure port. The low-pressure port is usually located on the passenger side of the engine compartment. It will be a small metal fitting with a blue cap.
2. Connect the A/C recharge hose to the low-pressure port. The A/C recharge hose is a flexible hose with a quick-connect fitting on one end. Screw the quick-connect fitting onto the low-pressure port.
3. Start the engine and turn on the air conditioner. Let the engine run for a few minutes so that the A/C system can circulate the refrigerant.
4. Open the A/C recharge valve. This will allow the refrigerant to flow from the recharge hose into the A/C system.
5. Monitor the A/C system pressure. The pressure should rise as the refrigerant is added. The target pressure is usually between 30 and 50 psi.
6. Once the target pressure is reached, close the A/C recharge valve. Disconnect the A/C recharge hose from the low-pressure port.
7. Turn off the engine and let the A/C system cool down.
Your 2004 Lincoln Aviator's air conditioner should now be recharged and working properly.
