Ford F65Z-19D644-AA Pressure Relief Valve

The HVAC Pressure Switch is located on top of the hard line from the condenser to the air conditioning thermostatic expansion valve (TXV). The HVAC Pressure Switch detects low refrigerant line pressure, and switches the A/C system off, then back on again to provide higher pressure. If the pressure increases too high, the pressure cut-off switch (located in the high-pressure side of the system) shuts the system off. Have the air conditioning system recovered by a dealer service department or an automotive air conditioning shop before proceeding. On four-cylinder models, remove the under engine splash shield (if equipped), and the splash shield below the radiator. Unplug the electrical connector from the HVAC Pressure Switch. Unscrew and remove the HVAC Pressure Switch. Lubricate the switch O-ring with clean refrigerant oil of the correct type. Screw the new switch into place until hand tight, then tighten it securely. Reconnect the electrical connector. For four-cylinder models, install the splash shields. Have the system evacuated, recharged, and leak tested by the shop that discharged it.