To begin, discharge the air conditioning system and disconnect the negative battery cable. Then, unplug the electrical connector from the pressure switch near the top of the receiver-drier. Disconnect the refrigerant line from the receiver-drier, using a backup wrench to prevent twisting the tubing. Make sure to plug the open fittings to prevent dirt and moisture from entering. Next, remove the receiver-drier by loosening the mounting bracket bolts or clamping band screw, depending on the model. If a new receiver-drier is being installed, remove the Schrader valve and pour out the oil, noting the amount. Add fresh refrigerant oil to the new receiver-drier, equal to the amount removed from the old unit plus one ounce. Finally, reverse the removal process for installation and take the vehicle back to the shop for evacuation, charging, and leak testing of the A/C system.